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ckpts/llama-3b/global_step100/bf16_zero_pp_rank_138_mp_rank_02_optim_states.pt

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ckpts/llama-3b/global_step100/bf16_zero_pp_rank_186_mp_rank_00_optim_states.pt

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ckpts/llama-3b/global_step100/bf16_zero_pp_rank_18_mp_rank_02_optim_states.pt

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ckpts/llama-3b/global_step100/bf16_zero_pp_rank_253_mp_rank_03_optim_states.pt

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ckpts/llama-3b/global_step100/bf16_zero_pp_rank_4_mp_rank_02_optim_states.pt

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ckpts/llama-3b/global_step100/bf16_zero_pp_rank_96_mp_rank_03_optim_states.pt

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ckpts/llama-3b/global_step100/layer_08-model_00-model_states.pt

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+size 116407086

venv/lib/python3.10/site-packages/pandas/core/array_algos/__init__.py

@@ -0,0 +1,9 @@
+"""
+core.array_algos is for algorithms that operate on ndarray and ExtensionArray.
+These should:
+
+- Assume that any Index, Series, or DataFrame objects have already been unwrapped.
+- Assume that any list arguments have already been cast to ndarray/EA.
+- Not depend on Index, Series, or DataFrame, nor import any of these.
+- May dispatch to ExtensionArray methods, but should not import from core.arrays.
+"""

venv/lib/python3.10/site-packages/pandas/core/array_algos/datetimelike_accumulations.py

@@ -0,0 +1,67 @@
+"""
+datetimelke_accumulations.py is for accumulations of datetimelike extension arrays
+"""
+
+from __future__ import annotations
+
+from typing import Callable
+
+import numpy as np
+
+from pandas._libs import iNaT
+
+from pandas.core.dtypes.missing import isna
+
+
+def _cum_func(
+    func: Callable,
+    values: np.ndarray,
+    *,
+    skipna: bool = True,
+):
+    """
+    Accumulations for 1D datetimelike arrays.
+
+    Parameters
+    ----------
+    func : np.cumsum, np.maximum.accumulate, np.minimum.accumulate
+    values : np.ndarray
+        Numpy array with the values (can be of any dtype that support the
+        operation). Values is changed is modified inplace.
+    skipna : bool, default True
+        Whether to skip NA.
+    """
+    try:
+        fill_value = {
+            np.maximum.accumulate: np.iinfo(np.int64).min,
+            np.cumsum: 0,
+            np.minimum.accumulate: np.iinfo(np.int64).max,
+        }[func]
+    except KeyError:
+        raise ValueError(f"No accumulation for {func} implemented on BaseMaskedArray")
+
+    mask = isna(values)
+    y = values.view("i8")
+    y[mask] = fill_value
+
+    if not skipna:
+        mask = np.maximum.accumulate(mask)
+
+    result = func(y)
+    result[mask] = iNaT
+
+    if values.dtype.kind in "mM":
+        return result.view(values.dtype.base)
+    return result
+
+
+def cumsum(values: np.ndarray, *, skipna: bool = True) -> np.ndarray:
+    return _cum_func(np.cumsum, values, skipna=skipna)
+
+
+def cummin(values: np.ndarray, *, skipna: bool = True):
+    return _cum_func(np.minimum.accumulate, values, skipna=skipna)
+
+
+def cummax(values: np.ndarray, *, skipna: bool = True):
+    return _cum_func(np.maximum.accumulate, values, skipna=skipna)

venv/lib/python3.10/site-packages/pandas/core/array_algos/masked_accumulations.py

@@ -0,0 +1,90 @@
+"""
+masked_accumulations.py is for accumulation algorithms using a mask-based approach
+for missing values.
+"""
+
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    Callable,
+)
+
+import numpy as np
+
+if TYPE_CHECKING:
+    from pandas._typing import npt
+
+
+def _cum_func(
+    func: Callable,
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+):
+    """
+    Accumulations for 1D masked array.
+
+    We will modify values in place to replace NAs with the appropriate fill value.
+
+    Parameters
+    ----------
+    func : np.cumsum, np.cumprod, np.maximum.accumulate, np.minimum.accumulate
+    values : np.ndarray
+        Numpy array with the values (can be of any dtype that support the
+        operation).
+    mask : np.ndarray
+        Boolean numpy array (True values indicate missing values).
+    skipna : bool, default True
+        Whether to skip NA.
+    """
+    dtype_info: np.iinfo | np.finfo
+    if values.dtype.kind == "f":
+        dtype_info = np.finfo(values.dtype.type)
+    elif values.dtype.kind in "iu":
+        dtype_info = np.iinfo(values.dtype.type)
+    elif values.dtype.kind == "b":
+        # Max value of bool is 1, but since we are setting into a boolean
+        # array, 255 is fine as well. Min value has to be 0 when setting
+        # into the boolean array.
+        dtype_info = np.iinfo(np.uint8)
+    else:
+        raise NotImplementedError(
+            f"No masked accumulation defined for dtype {values.dtype.type}"
+        )
+    try:
+        fill_value = {
+            np.cumprod: 1,
+            np.maximum.accumulate: dtype_info.min,
+            np.cumsum: 0,
+            np.minimum.accumulate: dtype_info.max,
+        }[func]
+    except KeyError:
+        raise NotImplementedError(
+            f"No accumulation for {func} implemented on BaseMaskedArray"
+        )
+
+    values[mask] = fill_value
+
+    if not skipna:
+        mask = np.maximum.accumulate(mask)
+
+    values = func(values)
+    return values, mask
+
+
+def cumsum(values: np.ndarray, mask: npt.NDArray[np.bool_], *, skipna: bool = True):
+    return _cum_func(np.cumsum, values, mask, skipna=skipna)
+
+
+def cumprod(values: np.ndarray, mask: npt.NDArray[np.bool_], *, skipna: bool = True):
+    return _cum_func(np.cumprod, values, mask, skipna=skipna)
+
+
+def cummin(values: np.ndarray, mask: npt.NDArray[np.bool_], *, skipna: bool = True):
+    return _cum_func(np.minimum.accumulate, values, mask, skipna=skipna)
+
+
+def cummax(values: np.ndarray, mask: npt.NDArray[np.bool_], *, skipna: bool = True):
+    return _cum_func(np.maximum.accumulate, values, mask, skipna=skipna)

venv/lib/python3.10/site-packages/pandas/core/array_algos/masked_reductions.py

@@ -0,0 +1,197 @@
+"""
+masked_reductions.py is for reduction algorithms using a mask-based approach
+for missing values.
+"""
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    Callable,
+)
+import warnings
+
+import numpy as np
+
+from pandas._libs import missing as libmissing
+
+from pandas.core.nanops import check_below_min_count
+
+if TYPE_CHECKING:
+    from pandas._typing import (
+        AxisInt,
+        npt,
+    )
+
+
+def _reductions(
+    func: Callable,
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    min_count: int = 0,
+    axis: AxisInt | None = None,
+    **kwargs,
+):
+    """
+    Sum, mean or product for 1D masked array.
+
+    Parameters
+    ----------
+    func : np.sum or np.prod
+    values : np.ndarray
+        Numpy array with the values (can be of any dtype that support the
+        operation).
+    mask : np.ndarray[bool]
+        Boolean numpy array (True values indicate missing values).
+    skipna : bool, default True
+        Whether to skip NA.
+    min_count : int, default 0
+        The required number of valid values to perform the operation. If fewer than
+        ``min_count`` non-NA values are present the result will be NA.
+    axis : int, optional, default None
+    """
+    if not skipna:
+        if mask.any() or check_below_min_count(values.shape, None, min_count):
+            return libmissing.NA
+        else:
+            return func(values, axis=axis, **kwargs)
+    else:
+        if check_below_min_count(values.shape, mask, min_count) and (
+            axis is None or values.ndim == 1
+        ):
+            return libmissing.NA
+
+        return func(values, where=~mask, axis=axis, **kwargs)
+
+
+def sum(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    min_count: int = 0,
+    axis: AxisInt | None = None,
+):
+    return _reductions(
+        np.sum, values=values, mask=mask, skipna=skipna, min_count=min_count, axis=axis
+    )
+
+
+def prod(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    min_count: int = 0,
+    axis: AxisInt | None = None,
+):
+    return _reductions(
+        np.prod, values=values, mask=mask, skipna=skipna, min_count=min_count, axis=axis
+    )
+
+
+def _minmax(
+    func: Callable,
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    axis: AxisInt | None = None,
+):
+    """
+    Reduction for 1D masked array.
+
+    Parameters
+    ----------
+    func : np.min or np.max
+    values : np.ndarray
+        Numpy array with the values (can be of any dtype that support the
+        operation).
+    mask : np.ndarray[bool]
+        Boolean numpy array (True values indicate missing values).
+    skipna : bool, default True
+        Whether to skip NA.
+    axis : int, optional, default None
+    """
+    if not skipna:
+        if mask.any() or not values.size:
+            # min/max with empty array raise in numpy, pandas returns NA
+            return libmissing.NA
+        else:
+            return func(values, axis=axis)
+    else:
+        subset = values[~mask]
+        if subset.size:
+            return func(subset, axis=axis)
+        else:
+            # min/max with empty array raise in numpy, pandas returns NA
+            return libmissing.NA
+
+
+def min(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    axis: AxisInt | None = None,
+):
+    return _minmax(np.min, values=values, mask=mask, skipna=skipna, axis=axis)
+
+
+def max(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    axis: AxisInt | None = None,
+):
+    return _minmax(np.max, values=values, mask=mask, skipna=skipna, axis=axis)
+
+
+def mean(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    axis: AxisInt | None = None,
+):
+    if not values.size or mask.all():
+        return libmissing.NA
+    return _reductions(np.mean, values=values, mask=mask, skipna=skipna, axis=axis)
+
+
+def var(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    axis: AxisInt | None = None,
+    ddof: int = 1,
+):
+    if not values.size or mask.all():
+        return libmissing.NA
+
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore", RuntimeWarning)
+        return _reductions(
+            np.var, values=values, mask=mask, skipna=skipna, axis=axis, ddof=ddof
+        )
+
+
+def std(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    *,
+    skipna: bool = True,
+    axis: AxisInt | None = None,
+    ddof: int = 1,
+):
+    if not values.size or mask.all():
+        return libmissing.NA
+
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore", RuntimeWarning)
+        return _reductions(
+            np.std, values=values, mask=mask, skipna=skipna, axis=axis, ddof=ddof
+        )

venv/lib/python3.10/site-packages/pandas/core/array_algos/putmask.py

@@ -0,0 +1,149 @@
+"""
+EA-compatible analogue to np.putmask
+"""
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    Any,
+)
+
+import numpy as np
+
+from pandas._libs import lib
+
+from pandas.core.dtypes.cast import infer_dtype_from
+from pandas.core.dtypes.common import is_list_like
+
+from pandas.core.arrays import ExtensionArray
+
+if TYPE_CHECKING:
+    from pandas._typing import (
+        ArrayLike,
+        npt,
+    )
+
+    from pandas import MultiIndex
+
+
+def putmask_inplace(values: ArrayLike, mask: npt.NDArray[np.bool_], value: Any) -> None:
+    """
+    ExtensionArray-compatible implementation of np.putmask.  The main
+    difference is we do not handle repeating or truncating like numpy.
+
+    Parameters
+    ----------
+    values: np.ndarray or ExtensionArray
+    mask : np.ndarray[bool]
+        We assume extract_bool_array has already been called.
+    value : Any
+    """
+
+    if (
+        not isinstance(values, np.ndarray)
+        or (values.dtype == object and not lib.is_scalar(value))
+        # GH#43424: np.putmask raises TypeError if we cannot cast between types with
+        # rule = "safe", a stricter guarantee we may not have here
+        or (
+            isinstance(value, np.ndarray) and not np.can_cast(value.dtype, values.dtype)
+        )
+    ):
+        # GH#19266 using np.putmask gives unexpected results with listlike value
+        #  along with object dtype
+        if is_list_like(value) and len(value) == len(values):
+            values[mask] = value[mask]
+        else:
+            values[mask] = value
+    else:
+        # GH#37833 np.putmask is more performant than __setitem__
+        np.putmask(values, mask, value)
+
+
+def putmask_without_repeat(
+    values: np.ndarray, mask: npt.NDArray[np.bool_], new: Any
+) -> None:
+    """
+    np.putmask will truncate or repeat if `new` is a listlike with
+    len(new) != len(values).  We require an exact match.
+
+    Parameters
+    ----------
+    values : np.ndarray
+    mask : np.ndarray[bool]
+    new : Any
+    """
+    if getattr(new, "ndim", 0) >= 1:
+        new = new.astype(values.dtype, copy=False)
+
+    # TODO: this prob needs some better checking for 2D cases
+    nlocs = mask.sum()
+    if nlocs > 0 and is_list_like(new) and getattr(new, "ndim", 1) == 1:
+        shape = np.shape(new)
+        # np.shape compat for if setitem_datetimelike_compat
+        #  changed arraylike to list e.g. test_where_dt64_2d
+        if nlocs == shape[-1]:
+            # GH#30567
+            # If length of ``new`` is less than the length of ``values``,
+            # `np.putmask` would first repeat the ``new`` array and then
+            # assign the masked values hence produces incorrect result.
+            # `np.place` on the other hand uses the ``new`` values at it is
+            # to place in the masked locations of ``values``
+            np.place(values, mask, new)
+            # i.e. values[mask] = new
+        elif mask.shape[-1] == shape[-1] or shape[-1] == 1:
+            np.putmask(values, mask, new)
+        else:
+            raise ValueError("cannot assign mismatch length to masked array")
+    else:
+        np.putmask(values, mask, new)
+
+
+def validate_putmask(
+    values: ArrayLike | MultiIndex, mask: np.ndarray
+) -> tuple[npt.NDArray[np.bool_], bool]:
+    """
+    Validate mask and check if this putmask operation is a no-op.
+    """
+    mask = extract_bool_array(mask)
+    if mask.shape != values.shape:
+        raise ValueError("putmask: mask and data must be the same size")
+
+    noop = not mask.any()
+    return mask, noop
+
+
+def extract_bool_array(mask: ArrayLike) -> npt.NDArray[np.bool_]:
+    """
+    If we have a SparseArray or BooleanArray, convert it to ndarray[bool].
+    """
+    if isinstance(mask, ExtensionArray):
+        # We could have BooleanArray, Sparse[bool], ...
+        #  Except for BooleanArray, this is equivalent to just
+        #  np.asarray(mask, dtype=bool)
+        mask = mask.to_numpy(dtype=bool, na_value=False)
+
+    mask = np.asarray(mask, dtype=bool)
+    return mask
+
+
+def setitem_datetimelike_compat(values: np.ndarray, num_set: int, other):
+    """
+    Parameters
+    ----------
+    values : np.ndarray
+    num_set : int
+        For putmask, this is mask.sum()
+    other : Any
+    """
+    if values.dtype == object:
+        dtype, _ = infer_dtype_from(other)
+
+        if lib.is_np_dtype(dtype, "mM"):
+            # https://github.com/numpy/numpy/issues/12550
+            #  timedelta64 will incorrectly cast to int
+            if not is_list_like(other):
+                other = [other] * num_set
+            else:
+                other = list(other)
+
+    return other

venv/lib/python3.10/site-packages/pandas/core/array_algos/quantile.py

@@ -0,0 +1,226 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import numpy as np
+
+from pandas.core.dtypes.missing import (
+    isna,
+    na_value_for_dtype,
+)
+
+if TYPE_CHECKING:
+    from pandas._typing import (
+        ArrayLike,
+        Scalar,
+        npt,
+    )
+
+
+def quantile_compat(
+    values: ArrayLike, qs: npt.NDArray[np.float64], interpolation: str
+) -> ArrayLike:
+    """
+    Compute the quantiles of the given values for each quantile in `qs`.
+
+    Parameters
+    ----------
+    values : np.ndarray or ExtensionArray
+    qs : np.ndarray[float64]
+    interpolation : str
+
+    Returns
+    -------
+    np.ndarray or ExtensionArray
+    """
+    if isinstance(values, np.ndarray):
+        fill_value = na_value_for_dtype(values.dtype, compat=False)
+        mask = isna(values)
+        return quantile_with_mask(values, mask, fill_value, qs, interpolation)
+    else:
+        return values._quantile(qs, interpolation)
+
+
+def quantile_with_mask(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    fill_value,
+    qs: npt.NDArray[np.float64],
+    interpolation: str,
+) -> np.ndarray:
+    """
+    Compute the quantiles of the given values for each quantile in `qs`.
+
+    Parameters
+    ----------
+    values : np.ndarray
+        For ExtensionArray, this is _values_for_factorize()[0]
+    mask : np.ndarray[bool]
+        mask = isna(values)
+        For ExtensionArray, this is computed before calling _value_for_factorize
+    fill_value : Scalar
+        The value to interpret fill NA entries with
+        For ExtensionArray, this is _values_for_factorize()[1]
+    qs : np.ndarray[float64]
+    interpolation : str
+        Type of interpolation
+
+    Returns
+    -------
+    np.ndarray
+
+    Notes
+    -----
+    Assumes values is already 2D.  For ExtensionArray this means np.atleast_2d
+    has been called on _values_for_factorize()[0]
+
+    Quantile is computed along axis=1.
+    """
+    assert values.shape == mask.shape
+    if values.ndim == 1:
+        # unsqueeze, operate, re-squeeze
+        values = np.atleast_2d(values)
+        mask = np.atleast_2d(mask)
+        res_values = quantile_with_mask(values, mask, fill_value, qs, interpolation)
+        return res_values[0]
+
+    assert values.ndim == 2
+
+    is_empty = values.shape[1] == 0
+
+    if is_empty:
+        # create the array of na_values
+        # 2d len(values) * len(qs)
+        flat = np.array([fill_value] * len(qs))
+        result = np.repeat(flat, len(values)).reshape(len(values), len(qs))
+    else:
+        result = _nanpercentile(
+            values,
+            qs * 100.0,
+            na_value=fill_value,
+            mask=mask,
+            interpolation=interpolation,
+        )
+
+        result = np.asarray(result)
+        result = result.T
+
+    return result
+
+
+def _nanpercentile_1d(
+    values: np.ndarray,
+    mask: npt.NDArray[np.bool_],
+    qs: npt.NDArray[np.float64],
+    na_value: Scalar,
+    interpolation: str,
+) -> Scalar | np.ndarray:
+    """
+    Wrapper for np.percentile that skips missing values, specialized to
+    1-dimensional case.
+
+    Parameters
+    ----------
+    values : array over which to find quantiles
+    mask : ndarray[bool]
+        locations in values that should be considered missing
+    qs : np.ndarray[float64] of quantile indices to find
+    na_value : scalar
+        value to return for empty or all-null values
+    interpolation : str
+
+    Returns
+    -------
+    quantiles : scalar or array
+    """
+    # mask is Union[ExtensionArray, ndarray]
+    values = values[~mask]
+
+    if len(values) == 0:
+        # Can't pass dtype=values.dtype here bc we might have na_value=np.nan
+        #  with values.dtype=int64 see test_quantile_empty
+        # equiv: 'np.array([na_value] * len(qs))' but much faster
+        return np.full(len(qs), na_value)
+
+    return np.percentile(
+        values,
+        qs,
+        # error: No overload variant of "percentile" matches argument
+        # types "ndarray[Any, Any]", "ndarray[Any, dtype[floating[_64Bit]]]"
+        # , "Dict[str, str]"  [call-overload]
+        method=interpolation,  # type: ignore[call-overload]
+    )
+
+
+def _nanpercentile(
+    values: np.ndarray,
+    qs: npt.NDArray[np.float64],
+    *,
+    na_value,
+    mask: npt.NDArray[np.bool_],
+    interpolation: str,
+):
+    """
+    Wrapper for np.percentile that skips missing values.
+
+    Parameters
+    ----------
+    values : np.ndarray[ndim=2]  over which to find quantiles
+    qs : np.ndarray[float64] of quantile indices to find
+    na_value : scalar
+        value to return for empty or all-null values
+    mask : np.ndarray[bool]
+        locations in values that should be considered missing
+    interpolation : str
+
+    Returns
+    -------
+    quantiles : scalar or array
+    """
+
+    if values.dtype.kind in "mM":
+        # need to cast to integer to avoid rounding errors in numpy
+        result = _nanpercentile(
+            values.view("i8"),
+            qs=qs,
+            na_value=na_value.view("i8"),
+            mask=mask,
+            interpolation=interpolation,
+        )
+
+        # Note: we have to do `astype` and not view because in general we
+        #  have float result at this point, not i8
+        return result.astype(values.dtype)
+
+    if mask.any():
+        # Caller is responsible for ensuring mask shape match
+        assert mask.shape == values.shape
+        result = [
+            _nanpercentile_1d(val, m, qs, na_value, interpolation=interpolation)
+            for (val, m) in zip(list(values), list(mask))
+        ]
+        if values.dtype.kind == "f":
+            # preserve itemsize
+            result = np.asarray(result, dtype=values.dtype).T
+        else:
+            result = np.asarray(result).T
+            if (
+                result.dtype != values.dtype
+                and not mask.all()
+                and (result == result.astype(values.dtype, copy=False)).all()
+            ):
+                # mask.all() will never get cast back to int
+                # e.g. values id integer dtype and result is floating dtype,
+                #  only cast back to integer dtype if result values are all-integer.
+                result = result.astype(values.dtype, copy=False)
+        return result
+    else:
+        return np.percentile(
+            values,
+            qs,
+            axis=1,
+            # error: No overload variant of "percentile" matches argument types
+            # "ndarray[Any, Any]", "ndarray[Any, dtype[floating[_64Bit]]]",
+            # "int", "Dict[str, str]"  [call-overload]
+            method=interpolation,  # type: ignore[call-overload]
+        )

venv/lib/python3.10/site-packages/pandas/core/array_algos/replace.py

@@ -0,0 +1,152 @@
+"""
+Methods used by Block.replace and related methods.
+"""
+from __future__ import annotations
+
+import operator
+import re
+from re import Pattern
+from typing import (
+    TYPE_CHECKING,
+    Any,
+)
+
+import numpy as np
+
+from pandas.core.dtypes.common import (
+    is_bool,
+    is_re,
+    is_re_compilable,
+)
+from pandas.core.dtypes.missing import isna
+
+if TYPE_CHECKING:
+    from pandas._typing import (
+        ArrayLike,
+        Scalar,
+        npt,
+    )
+
+
+def should_use_regex(regex: bool, to_replace: Any) -> bool:
+    """
+    Decide whether to treat `to_replace` as a regular expression.
+    """
+    if is_re(to_replace):
+        regex = True
+
+    regex = regex and is_re_compilable(to_replace)
+
+    # Don't use regex if the pattern is empty.
+    regex = regex and re.compile(to_replace).pattern != ""
+    return regex
+
+
+def compare_or_regex_search(
+    a: ArrayLike, b: Scalar | Pattern, regex: bool, mask: npt.NDArray[np.bool_]
+) -> ArrayLike:
+    """
+    Compare two array-like inputs of the same shape or two scalar values
+
+    Calls operator.eq or re.search, depending on regex argument. If regex is
+    True, perform an element-wise regex matching.
+
+    Parameters
+    ----------
+    a : array-like
+    b : scalar or regex pattern
+    regex : bool
+    mask : np.ndarray[bool]
+
+    Returns
+    -------
+    mask : array-like of bool
+    """
+    if isna(b):
+        return ~mask
+
+    def _check_comparison_types(
+        result: ArrayLike | bool, a: ArrayLike, b: Scalar | Pattern
+    ):
+        """
+        Raises an error if the two arrays (a,b) cannot be compared.
+        Otherwise, returns the comparison result as expected.
+        """
+        if is_bool(result) and isinstance(a, np.ndarray):
+            type_names = [type(a).__name__, type(b).__name__]
+
+            type_names[0] = f"ndarray(dtype={a.dtype})"
+
+            raise TypeError(
+                f"Cannot compare types {repr(type_names[0])} and {repr(type_names[1])}"
+            )
+
+    if not regex or not should_use_regex(regex, b):
+        # TODO: should use missing.mask_missing?
+        op = lambda x: operator.eq(x, b)
+    else:
+        op = np.vectorize(
+            lambda x: bool(re.search(b, x))
+            if isinstance(x, str) and isinstance(b, (str, Pattern))
+            else False
+        )
+
+    # GH#32621 use mask to avoid comparing to NAs
+    if isinstance(a, np.ndarray):
+        a = a[mask]
+
+    result = op(a)
+
+    if isinstance(result, np.ndarray) and mask is not None:
+        # The shape of the mask can differ to that of the result
+        # since we may compare only a subset of a's or b's elements
+        tmp = np.zeros(mask.shape, dtype=np.bool_)
+        np.place(tmp, mask, result)
+        result = tmp
+
+    _check_comparison_types(result, a, b)
+    return result
+
+
+def replace_regex(
+    values: ArrayLike, rx: re.Pattern, value, mask: npt.NDArray[np.bool_] | None
+) -> None:
+    """
+    Parameters
+    ----------
+    values : ArrayLike
+        Object dtype.
+    rx : re.Pattern
+    value : Any
+    mask : np.ndarray[bool], optional
+
+    Notes
+    -----
+    Alters values in-place.
+    """
+
+    # deal with replacing values with objects (strings) that match but
+    # whose replacement is not a string (numeric, nan, object)
+    if isna(value) or not isinstance(value, str):
+
+        def re_replacer(s):
+            if is_re(rx) and isinstance(s, str):
+                return value if rx.search(s) is not None else s
+            else:
+                return s
+
+    else:
+        # value is guaranteed to be a string here, s can be either a string
+        # or null if it's null it gets returned
+        def re_replacer(s):
+            if is_re(rx) and isinstance(s, str):
+                return rx.sub(value, s)
+            else:
+                return s
+
+    f = np.vectorize(re_replacer, otypes=[np.object_])
+
+    if mask is None:
+        values[:] = f(values)
+    else:
+        values[mask] = f(values[mask])

venv/lib/python3.10/site-packages/pandas/core/array_algos/take.py

@@ -0,0 +1,594 @@
+from __future__ import annotations
+
+import functools
+from typing import (
+    TYPE_CHECKING,
+    cast,
+    overload,
+)
+
+import numpy as np
+
+from pandas._libs import (
+    algos as libalgos,
+    lib,
+)
+
+from pandas.core.dtypes.cast import maybe_promote
+from pandas.core.dtypes.common import (
+    ensure_platform_int,
+    is_1d_only_ea_dtype,
+)
+from pandas.core.dtypes.missing import na_value_for_dtype
+
+from pandas.core.construction import ensure_wrapped_if_datetimelike
+
+if TYPE_CHECKING:
+    from pandas._typing import (
+        ArrayLike,
+        AxisInt,
+        npt,
+    )
+
+    from pandas.core.arrays._mixins import NDArrayBackedExtensionArray
+    from pandas.core.arrays.base import ExtensionArray
+
+
+@overload
+def take_nd(
+    arr: np.ndarray,
+    indexer,
+    axis: AxisInt = ...,
+    fill_value=...,
+    allow_fill: bool = ...,
+) -> np.ndarray:
+    ...
+
+
+@overload
+def take_nd(
+    arr: ExtensionArray,
+    indexer,
+    axis: AxisInt = ...,
+    fill_value=...,
+    allow_fill: bool = ...,
+) -> ArrayLike:
+    ...
+
+
+def take_nd(
+    arr: ArrayLike,
+    indexer,
+    axis: AxisInt = 0,
+    fill_value=lib.no_default,
+    allow_fill: bool = True,
+) -> ArrayLike:
+    """
+    Specialized Cython take which sets NaN values in one pass
+
+    This dispatches to ``take`` defined on ExtensionArrays.
+
+    Note: this function assumes that the indexer is a valid(ated) indexer with
+    no out of bound indices.
+
+    Parameters
+    ----------
+    arr : np.ndarray or ExtensionArray
+        Input array.
+    indexer : ndarray
+        1-D array of indices to take, subarrays corresponding to -1 value
+        indices are filed with fill_value
+    axis : int, default 0
+        Axis to take from
+    fill_value : any, default np.nan
+        Fill value to replace -1 values with
+    allow_fill : bool, default True
+        If False, indexer is assumed to contain no -1 values so no filling
+        will be done.  This short-circuits computation of a mask.  Result is
+        undefined if allow_fill == False and -1 is present in indexer.
+
+    Returns
+    -------
+    subarray : np.ndarray or ExtensionArray
+        May be the same type as the input, or cast to an ndarray.
+    """
+    if fill_value is lib.no_default:
+        fill_value = na_value_for_dtype(arr.dtype, compat=False)
+    elif lib.is_np_dtype(arr.dtype, "mM"):
+        dtype, fill_value = maybe_promote(arr.dtype, fill_value)
+        if arr.dtype != dtype:
+            # EA.take is strict about returning a new object of the same type
+            # so for that case cast upfront
+            arr = arr.astype(dtype)
+
+    if not isinstance(arr, np.ndarray):
+        # i.e. ExtensionArray,
+        # includes for EA to catch DatetimeArray, TimedeltaArray
+        if not is_1d_only_ea_dtype(arr.dtype):
+            # i.e. DatetimeArray, TimedeltaArray
+            arr = cast("NDArrayBackedExtensionArray", arr)
+            return arr.take(
+                indexer, fill_value=fill_value, allow_fill=allow_fill, axis=axis
+            )
+
+        return arr.take(indexer, fill_value=fill_value, allow_fill=allow_fill)
+
+    arr = np.asarray(arr)
+    return _take_nd_ndarray(arr, indexer, axis, fill_value, allow_fill)
+
+
+def _take_nd_ndarray(
+    arr: np.ndarray,
+    indexer: npt.NDArray[np.intp] | None,
+    axis: AxisInt,
+    fill_value,
+    allow_fill: bool,
+) -> np.ndarray:
+    if indexer is None:
+        indexer = np.arange(arr.shape[axis], dtype=np.intp)
+        dtype, fill_value = arr.dtype, arr.dtype.type()
+    else:
+        indexer = ensure_platform_int(indexer)
+
+    dtype, fill_value, mask_info = _take_preprocess_indexer_and_fill_value(
+        arr, indexer, fill_value, allow_fill
+    )
+
+    flip_order = False
+    if arr.ndim == 2 and arr.flags.f_contiguous:
+        flip_order = True
+
+    if flip_order:
+        arr = arr.T
+        axis = arr.ndim - axis - 1
+
+    # at this point, it's guaranteed that dtype can hold both the arr values
+    # and the fill_value
+    out_shape_ = list(arr.shape)
+    out_shape_[axis] = len(indexer)
+    out_shape = tuple(out_shape_)
+    if arr.flags.f_contiguous and axis == arr.ndim - 1:
+        # minor tweak that can make an order-of-magnitude difference
+        # for dataframes initialized directly from 2-d ndarrays
+        # (s.t. df.values is c-contiguous and df._mgr.blocks[0] is its
+        # f-contiguous transpose)
+        out = np.empty(out_shape, dtype=dtype, order="F")
+    else:
+        out = np.empty(out_shape, dtype=dtype)
+
+    func = _get_take_nd_function(
+        arr.ndim, arr.dtype, out.dtype, axis=axis, mask_info=mask_info
+    )
+    func(arr, indexer, out, fill_value)
+
+    if flip_order:
+        out = out.T
+    return out
+
+
+def take_1d(
+    arr: ArrayLike,
+    indexer: npt.NDArray[np.intp],
+    fill_value=None,
+    allow_fill: bool = True,
+    mask: npt.NDArray[np.bool_] | None = None,
+) -> ArrayLike:
+    """
+    Specialized version for 1D arrays. Differences compared to `take_nd`:
+
+    - Assumes input array has already been converted to numpy array / EA
+    - Assumes indexer is already guaranteed to be intp dtype ndarray
+    - Only works for 1D arrays
+
+    To ensure the lowest possible overhead.
+
+    Note: similarly to `take_nd`, this function assumes that the indexer is
+    a valid(ated) indexer with no out of bound indices.
+
+    Parameters
+    ----------
+    arr : np.ndarray or ExtensionArray
+        Input array.
+    indexer : ndarray
+        1-D array of indices to take (validated indices, intp dtype).
+    fill_value : any, default np.nan
+        Fill value to replace -1 values with
+    allow_fill : bool, default True
+        If False, indexer is assumed to contain no -1 values so no filling
+        will be done.  This short-circuits computation of a mask. Result is
+        undefined if allow_fill == False and -1 is present in indexer.
+    mask : np.ndarray, optional, default None
+        If `allow_fill` is True, and the mask (where indexer == -1) is already
+        known, it can be passed to avoid recomputation.
+    """
+    if not isinstance(arr, np.ndarray):
+        # ExtensionArray -> dispatch to their method
+        return arr.take(indexer, fill_value=fill_value, allow_fill=allow_fill)
+
+    if not allow_fill:
+        return arr.take(indexer)
+
+    dtype, fill_value, mask_info = _take_preprocess_indexer_and_fill_value(
+        arr, indexer, fill_value, True, mask
+    )
+
+    # at this point, it's guaranteed that dtype can hold both the arr values
+    # and the fill_value
+    out = np.empty(indexer.shape, dtype=dtype)
+
+    func = _get_take_nd_function(
+        arr.ndim, arr.dtype, out.dtype, axis=0, mask_info=mask_info
+    )
+    func(arr, indexer, out, fill_value)
+
+    return out
+
+
+def take_2d_multi(
+    arr: np.ndarray,
+    indexer: tuple[npt.NDArray[np.intp], npt.NDArray[np.intp]],
+    fill_value=np.nan,
+) -> np.ndarray:
+    """
+    Specialized Cython take which sets NaN values in one pass.
+    """
+    # This is only called from one place in DataFrame._reindex_multi,
+    #  so we know indexer is well-behaved.
+    assert indexer is not None
+    assert indexer[0] is not None
+    assert indexer[1] is not None
+
+    row_idx, col_idx = indexer
+
+    row_idx = ensure_platform_int(row_idx)
+    col_idx = ensure_platform_int(col_idx)
+    indexer = row_idx, col_idx
+    mask_info = None
+
+    # check for promotion based on types only (do this first because
+    # it's faster than computing a mask)
+    dtype, fill_value = maybe_promote(arr.dtype, fill_value)
+    if dtype != arr.dtype:
+        # check if promotion is actually required based on indexer
+        row_mask = row_idx == -1
+        col_mask = col_idx == -1
+        row_needs = row_mask.any()
+        col_needs = col_mask.any()
+        mask_info = (row_mask, col_mask), (row_needs, col_needs)
+
+        if not (row_needs or col_needs):
+            # if not, then depromote, set fill_value to dummy
+            # (it won't be used but we don't want the cython code
+            # to crash when trying to cast it to dtype)
+            dtype, fill_value = arr.dtype, arr.dtype.type()
+
+    # at this point, it's guaranteed that dtype can hold both the arr values
+    # and the fill_value
+    out_shape = len(row_idx), len(col_idx)
+    out = np.empty(out_shape, dtype=dtype)
+
+    func = _take_2d_multi_dict.get((arr.dtype.name, out.dtype.name), None)
+    if func is None and arr.dtype != out.dtype:
+        func = _take_2d_multi_dict.get((out.dtype.name, out.dtype.name), None)
+        if func is not None:
+            func = _convert_wrapper(func, out.dtype)
+
+    if func is not None:
+        func(arr, indexer, out=out, fill_value=fill_value)
+    else:
+        # test_reindex_multi
+        _take_2d_multi_object(
+            arr, indexer, out, fill_value=fill_value, mask_info=mask_info
+        )
+
+    return out
+
+
+@functools.lru_cache
+def _get_take_nd_function_cached(
+    ndim: int, arr_dtype: np.dtype, out_dtype: np.dtype, axis: AxisInt
+):
+    """
+    Part of _get_take_nd_function below that doesn't need `mask_info` and thus
+    can be cached (mask_info potentially contains a numpy ndarray which is not
+    hashable and thus cannot be used as argument for cached function).
+    """
+    tup = (arr_dtype.name, out_dtype.name)
+    if ndim == 1:
+        func = _take_1d_dict.get(tup, None)
+    elif ndim == 2:
+        if axis == 0:
+            func = _take_2d_axis0_dict.get(tup, None)
+        else:
+            func = _take_2d_axis1_dict.get(tup, None)
+    if func is not None:
+        return func
+
+    # We get here with string, uint, float16, and complex dtypes that could
+    #  potentially be handled in algos_take_helper.
+    #  Also a couple with (M8[ns], object) and (m8[ns], object)
+    tup = (out_dtype.name, out_dtype.name)
+    if ndim == 1:
+        func = _take_1d_dict.get(tup, None)
+    elif ndim == 2:
+        if axis == 0:
+            func = _take_2d_axis0_dict.get(tup, None)
+        else:
+            func = _take_2d_axis1_dict.get(tup, None)
+    if func is not None:
+        func = _convert_wrapper(func, out_dtype)
+        return func
+
+    return None
+
+
+def _get_take_nd_function(
+    ndim: int,
+    arr_dtype: np.dtype,
+    out_dtype: np.dtype,
+    axis: AxisInt = 0,
+    mask_info=None,
+):
+    """
+    Get the appropriate "take" implementation for the given dimension, axis
+    and dtypes.
+    """
+    func = None
+    if ndim <= 2:
+        # for this part we don't need `mask_info` -> use the cached algo lookup
+        func = _get_take_nd_function_cached(ndim, arr_dtype, out_dtype, axis)
+
+    if func is None:
+
+        def func(arr, indexer, out, fill_value=np.nan) -> None:
+            indexer = ensure_platform_int(indexer)
+            _take_nd_object(
+                arr, indexer, out, axis=axis, fill_value=fill_value, mask_info=mask_info
+            )
+
+    return func
+
+
+def _view_wrapper(f, arr_dtype=None, out_dtype=None, fill_wrap=None):
+    def wrapper(
+        arr: np.ndarray, indexer: np.ndarray, out: np.ndarray, fill_value=np.nan
+    ) -> None:
+        if arr_dtype is not None:
+            arr = arr.view(arr_dtype)
+        if out_dtype is not None:
+            out = out.view(out_dtype)
+        if fill_wrap is not None:
+            # FIXME: if we get here with dt64/td64 we need to be sure we have
+            #  matching resos
+            if fill_value.dtype.kind == "m":
+                fill_value = fill_value.astype("m8[ns]")
+            else:
+                fill_value = fill_value.astype("M8[ns]")
+            fill_value = fill_wrap(fill_value)
+
+        f(arr, indexer, out, fill_value=fill_value)
+
+    return wrapper
+
+
+def _convert_wrapper(f, conv_dtype):
+    def wrapper(
+        arr: np.ndarray, indexer: np.ndarray, out: np.ndarray, fill_value=np.nan
+    ) -> None:
+        if conv_dtype == object:
+            # GH#39755 avoid casting dt64/td64 to integers
+            arr = ensure_wrapped_if_datetimelike(arr)
+        arr = arr.astype(conv_dtype)
+        f(arr, indexer, out, fill_value=fill_value)
+
+    return wrapper
+
+
+_take_1d_dict = {
+    ("int8", "int8"): libalgos.take_1d_int8_int8,
+    ("int8", "int32"): libalgos.take_1d_int8_int32,
+    ("int8", "int64"): libalgos.take_1d_int8_int64,
+    ("int8", "float64"): libalgos.take_1d_int8_float64,
+    ("int16", "int16"): libalgos.take_1d_int16_int16,
+    ("int16", "int32"): libalgos.take_1d_int16_int32,
+    ("int16", "int64"): libalgos.take_1d_int16_int64,
+    ("int16", "float64"): libalgos.take_1d_int16_float64,
+    ("int32", "int32"): libalgos.take_1d_int32_int32,
+    ("int32", "int64"): libalgos.take_1d_int32_int64,
+    ("int32", "float64"): libalgos.take_1d_int32_float64,
+    ("int64", "int64"): libalgos.take_1d_int64_int64,
+    ("int64", "float64"): libalgos.take_1d_int64_float64,
+    ("float32", "float32"): libalgos.take_1d_float32_float32,
+    ("float32", "float64"): libalgos.take_1d_float32_float64,
+    ("float64", "float64"): libalgos.take_1d_float64_float64,
+    ("object", "object"): libalgos.take_1d_object_object,
+    ("bool", "bool"): _view_wrapper(libalgos.take_1d_bool_bool, np.uint8, np.uint8),
+    ("bool", "object"): _view_wrapper(libalgos.take_1d_bool_object, np.uint8, None),
+    ("datetime64[ns]", "datetime64[ns]"): _view_wrapper(
+        libalgos.take_1d_int64_int64, np.int64, np.int64, np.int64
+    ),
+    ("timedelta64[ns]", "timedelta64[ns]"): _view_wrapper(
+        libalgos.take_1d_int64_int64, np.int64, np.int64, np.int64
+    ),
+}
+
+_take_2d_axis0_dict = {
+    ("int8", "int8"): libalgos.take_2d_axis0_int8_int8,
+    ("int8", "int32"): libalgos.take_2d_axis0_int8_int32,
+    ("int8", "int64"): libalgos.take_2d_axis0_int8_int64,
+    ("int8", "float64"): libalgos.take_2d_axis0_int8_float64,
+    ("int16", "int16"): libalgos.take_2d_axis0_int16_int16,
+    ("int16", "int32"): libalgos.take_2d_axis0_int16_int32,
+    ("int16", "int64"): libalgos.take_2d_axis0_int16_int64,
+    ("int16", "float64"): libalgos.take_2d_axis0_int16_float64,
+    ("int32", "int32"): libalgos.take_2d_axis0_int32_int32,
+    ("int32", "int64"): libalgos.take_2d_axis0_int32_int64,
+    ("int32", "float64"): libalgos.take_2d_axis0_int32_float64,
+    ("int64", "int64"): libalgos.take_2d_axis0_int64_int64,
+    ("int64", "float64"): libalgos.take_2d_axis0_int64_float64,
+    ("float32", "float32"): libalgos.take_2d_axis0_float32_float32,
+    ("float32", "float64"): libalgos.take_2d_axis0_float32_float64,
+    ("float64", "float64"): libalgos.take_2d_axis0_float64_float64,
+    ("object", "object"): libalgos.take_2d_axis0_object_object,
+    ("bool", "bool"): _view_wrapper(
+        libalgos.take_2d_axis0_bool_bool, np.uint8, np.uint8
+    ),
+    ("bool", "object"): _view_wrapper(
+        libalgos.take_2d_axis0_bool_object, np.uint8, None
+    ),
+    ("datetime64[ns]", "datetime64[ns]"): _view_wrapper(
+        libalgos.take_2d_axis0_int64_int64, np.int64, np.int64, fill_wrap=np.int64
+    ),
+    ("timedelta64[ns]", "timedelta64[ns]"): _view_wrapper(
+        libalgos.take_2d_axis0_int64_int64, np.int64, np.int64, fill_wrap=np.int64
+    ),
+}
+
+_take_2d_axis1_dict = {
+    ("int8", "int8"): libalgos.take_2d_axis1_int8_int8,
+    ("int8", "int32"): libalgos.take_2d_axis1_int8_int32,
+    ("int8", "int64"): libalgos.take_2d_axis1_int8_int64,
+    ("int8", "float64"): libalgos.take_2d_axis1_int8_float64,
+    ("int16", "int16"): libalgos.take_2d_axis1_int16_int16,
+    ("int16", "int32"): libalgos.take_2d_axis1_int16_int32,
+    ("int16", "int64"): libalgos.take_2d_axis1_int16_int64,
+    ("int16", "float64"): libalgos.take_2d_axis1_int16_float64,
+    ("int32", "int32"): libalgos.take_2d_axis1_int32_int32,
+    ("int32", "int64"): libalgos.take_2d_axis1_int32_int64,
+    ("int32", "float64"): libalgos.take_2d_axis1_int32_float64,
+    ("int64", "int64"): libalgos.take_2d_axis1_int64_int64,
+    ("int64", "float64"): libalgos.take_2d_axis1_int64_float64,
+    ("float32", "float32"): libalgos.take_2d_axis1_float32_float32,
+    ("float32", "float64"): libalgos.take_2d_axis1_float32_float64,
+    ("float64", "float64"): libalgos.take_2d_axis1_float64_float64,
+    ("object", "object"): libalgos.take_2d_axis1_object_object,
+    ("bool", "bool"): _view_wrapper(
+        libalgos.take_2d_axis1_bool_bool, np.uint8, np.uint8
+    ),
+    ("bool", "object"): _view_wrapper(
+        libalgos.take_2d_axis1_bool_object, np.uint8, None
+    ),
+    ("datetime64[ns]", "datetime64[ns]"): _view_wrapper(
+        libalgos.take_2d_axis1_int64_int64, np.int64, np.int64, fill_wrap=np.int64
+    ),
+    ("timedelta64[ns]", "timedelta64[ns]"): _view_wrapper(
+        libalgos.take_2d_axis1_int64_int64, np.int64, np.int64, fill_wrap=np.int64
+    ),
+}
+
+_take_2d_multi_dict = {
+    ("int8", "int8"): libalgos.take_2d_multi_int8_int8,
+    ("int8", "int32"): libalgos.take_2d_multi_int8_int32,
+    ("int8", "int64"): libalgos.take_2d_multi_int8_int64,
+    ("int8", "float64"): libalgos.take_2d_multi_int8_float64,
+    ("int16", "int16"): libalgos.take_2d_multi_int16_int16,
+    ("int16", "int32"): libalgos.take_2d_multi_int16_int32,
+    ("int16", "int64"): libalgos.take_2d_multi_int16_int64,
+    ("int16", "float64"): libalgos.take_2d_multi_int16_float64,
+    ("int32", "int32"): libalgos.take_2d_multi_int32_int32,
+    ("int32", "int64"): libalgos.take_2d_multi_int32_int64,
+    ("int32", "float64"): libalgos.take_2d_multi_int32_float64,
+    ("int64", "int64"): libalgos.take_2d_multi_int64_int64,
+    ("int64", "float64"): libalgos.take_2d_multi_int64_float64,
+    ("float32", "float32"): libalgos.take_2d_multi_float32_float32,
+    ("float32", "float64"): libalgos.take_2d_multi_float32_float64,
+    ("float64", "float64"): libalgos.take_2d_multi_float64_float64,
+    ("object", "object"): libalgos.take_2d_multi_object_object,
+    ("bool", "bool"): _view_wrapper(
+        libalgos.take_2d_multi_bool_bool, np.uint8, np.uint8
+    ),
+    ("bool", "object"): _view_wrapper(
+        libalgos.take_2d_multi_bool_object, np.uint8, None
+    ),
+    ("datetime64[ns]", "datetime64[ns]"): _view_wrapper(
+        libalgos.take_2d_multi_int64_int64, np.int64, np.int64, fill_wrap=np.int64
+    ),
+    ("timedelta64[ns]", "timedelta64[ns]"): _view_wrapper(
+        libalgos.take_2d_multi_int64_int64, np.int64, np.int64, fill_wrap=np.int64
+    ),
+}
+
+
+def _take_nd_object(
+    arr: np.ndarray,
+    indexer: npt.NDArray[np.intp],
+    out: np.ndarray,
+    axis: AxisInt,
+    fill_value,
+    mask_info,
+) -> None:
+    if mask_info is not None:
+        mask, needs_masking = mask_info
+    else:
+        mask = indexer == -1
+        needs_masking = mask.any()
+    if arr.dtype != out.dtype:
+        arr = arr.astype(out.dtype)
+    if arr.shape[axis] > 0:
+        arr.take(indexer, axis=axis, out=out)
+    if needs_masking:
+        outindexer = [slice(None)] * arr.ndim
+        outindexer[axis] = mask
+        out[tuple(outindexer)] = fill_value
+
+
+def _take_2d_multi_object(
+    arr: np.ndarray,
+    indexer: tuple[npt.NDArray[np.intp], npt.NDArray[np.intp]],
+    out: np.ndarray,
+    fill_value,
+    mask_info,
+) -> None:
+    # this is not ideal, performance-wise, but it's better than raising
+    # an exception (best to optimize in Cython to avoid getting here)
+    row_idx, col_idx = indexer  # both np.intp
+    if mask_info is not None:
+        (row_mask, col_mask), (row_needs, col_needs) = mask_info
+    else:
+        row_mask = row_idx == -1
+        col_mask = col_idx == -1
+        row_needs = row_mask.any()
+        col_needs = col_mask.any()
+    if fill_value is not None:
+        if row_needs:
+            out[row_mask, :] = fill_value
+        if col_needs:
+            out[:, col_mask] = fill_value
+    for i, u_ in enumerate(row_idx):
+        if u_ != -1:
+            for j, v in enumerate(col_idx):
+                if v != -1:
+                    out[i, j] = arr[u_, v]
+
+
+def _take_preprocess_indexer_and_fill_value(
+    arr: np.ndarray,
+    indexer: npt.NDArray[np.intp],
+    fill_value,
+    allow_fill: bool,
+    mask: npt.NDArray[np.bool_] | None = None,
+):
+    mask_info: tuple[np.ndarray | None, bool] | None = None
+
+    if not allow_fill:
+        dtype, fill_value = arr.dtype, arr.dtype.type()
+        mask_info = None, False
+    else:
+        # check for promotion based on types only (do this first because
+        # it's faster than computing a mask)
+        dtype, fill_value = maybe_promote(arr.dtype, fill_value)
+        if dtype != arr.dtype:
+            # check if promotion is actually required based on indexer
+            if mask is not None:
+                needs_masking = True
+            else:
+                mask = indexer == -1
+                needs_masking = bool(mask.any())
+            mask_info = mask, needs_masking
+            if not needs_masking:
+                # if not, then depromote, set fill_value to dummy
+                # (it won't be used but we don't want the cython code
+                # to crash when trying to cast it to dtype)
+                dtype, fill_value = arr.dtype, arr.dtype.type()
+
+    return dtype, fill_value, mask_info

venv/lib/python3.10/site-packages/pandas/core/array_algos/transforms.py

@@ -0,0 +1,50 @@
+"""
+transforms.py is for shape-preserving functions.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import numpy as np
+
+if TYPE_CHECKING:
+    from pandas._typing import (
+        AxisInt,
+        Scalar,
+    )
+
+
+def shift(
+    values: np.ndarray, periods: int, axis: AxisInt, fill_value: Scalar
+) -> np.ndarray:
+    new_values = values
+
+    if periods == 0 or values.size == 0:
+        return new_values.copy()
+
+    # make sure array sent to np.roll is c_contiguous
+    f_ordered = values.flags.f_contiguous
+    if f_ordered:
+        new_values = new_values.T
+        axis = new_values.ndim - axis - 1
+
+    if new_values.size:
+        new_values = np.roll(
+            new_values,
+            np.intp(periods),
+            axis=axis,
+        )
+
+    axis_indexer = [slice(None)] * values.ndim
+    if periods > 0:
+        axis_indexer[axis] = slice(None, periods)
+    else:
+        axis_indexer[axis] = slice(periods, None)
+    new_values[tuple(axis_indexer)] = fill_value
+
+    # restore original order
+    if f_ordered:
+        new_values = new_values.T
+
+    return new_values

venv/lib/python3.10/site-packages/pandas/core/dtypes/cast.py

@@ -0,0 +1,1973 @@
+"""
+Routines for casting.
+"""
+
+from __future__ import annotations
+
+import datetime as dt
+import functools
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Literal,
+    TypeVar,
+    cast,
+    overload,
+)
+import warnings
+
+import numpy as np
+
+from pandas._config import using_pyarrow_string_dtype
+
+from pandas._libs import (
+    Interval,
+    Period,
+    lib,
+)
+from pandas._libs.missing import (
+    NA,
+    NAType,
+    checknull,
+)
+from pandas._libs.tslibs import (
+    NaT,
+    OutOfBoundsDatetime,
+    OutOfBoundsTimedelta,
+    Timedelta,
+    Timestamp,
+    is_supported_dtype,
+)
+from pandas._libs.tslibs.timedeltas import array_to_timedelta64
+from pandas.compat.numpy import np_version_gt2
+from pandas.errors import (
+    IntCastingNaNError,
+    LossySetitemError,
+)
+
+from pandas.core.dtypes.common import (
+    ensure_int8,
+    ensure_int16,
+    ensure_int32,
+    ensure_int64,
+    ensure_object,
+    ensure_str,
+    is_bool,
+    is_complex,
+    is_float,
+    is_integer,
+    is_object_dtype,
+    is_scalar,
+    is_string_dtype,
+    pandas_dtype as pandas_dtype_func,
+)
+from pandas.core.dtypes.dtypes import (
+    ArrowDtype,
+    BaseMaskedDtype,
+    CategoricalDtype,
+    DatetimeTZDtype,
+    ExtensionDtype,
+    IntervalDtype,
+    PandasExtensionDtype,
+    PeriodDtype,
+)
+from pandas.core.dtypes.generic import (
+    ABCExtensionArray,
+    ABCIndex,
+    ABCSeries,
+)
+from pandas.core.dtypes.inference import is_list_like
+from pandas.core.dtypes.missing import (
+    is_valid_na_for_dtype,
+    isna,
+    na_value_for_dtype,
+    notna,
+)
+
+from pandas.io._util import _arrow_dtype_mapping
+
+if TYPE_CHECKING:
+    from collections.abc import (
+        Sequence,
+        Sized,
+    )
+
+    from pandas._typing import (
+        ArrayLike,
+        Dtype,
+        DtypeObj,
+        NumpyIndexT,
+        Scalar,
+        npt,
+    )
+
+    from pandas import Index
+    from pandas.core.arrays import (
+        Categorical,
+        DatetimeArray,
+        ExtensionArray,
+        IntervalArray,
+        PeriodArray,
+        TimedeltaArray,
+    )
+
+
+_int8_max = np.iinfo(np.int8).max
+_int16_max = np.iinfo(np.int16).max
+_int32_max = np.iinfo(np.int32).max
+
+_dtype_obj = np.dtype(object)
+
+NumpyArrayT = TypeVar("NumpyArrayT", bound=np.ndarray)
+
+
+def maybe_convert_platform(
+    values: list | tuple | range | np.ndarray | ExtensionArray,
+) -> ArrayLike:
+    """try to do platform conversion, allow ndarray or list here"""
+    arr: ArrayLike
+
+    if isinstance(values, (list, tuple, range)):
+        arr = construct_1d_object_array_from_listlike(values)
+    else:
+        # The caller is responsible for ensuring that we have np.ndarray
+        #  or ExtensionArray here.
+        arr = values
+
+    if arr.dtype == _dtype_obj:
+        arr = cast(np.ndarray, arr)
+        arr = lib.maybe_convert_objects(arr)
+
+    return arr
+
+
+def is_nested_object(obj) -> bool:
+    """
+    return a boolean if we have a nested object, e.g. a Series with 1 or
+    more Series elements
+
+    This may not be necessarily be performant.
+
+    """
+    return bool(
+        isinstance(obj, ABCSeries)
+        and is_object_dtype(obj.dtype)
+        and any(isinstance(v, ABCSeries) for v in obj._values)
+    )
+
+
+def maybe_box_datetimelike(value: Scalar, dtype: Dtype | None = None) -> Scalar:
+    """
+    Cast scalar to Timestamp or Timedelta if scalar is datetime-like
+    and dtype is not object.
+
+    Parameters
+    ----------
+    value : scalar
+    dtype : Dtype, optional
+
+    Returns
+    -------
+    scalar
+    """
+    if dtype == _dtype_obj:
+        pass
+    elif isinstance(value, (np.datetime64, dt.datetime)):
+        value = Timestamp(value)
+    elif isinstance(value, (np.timedelta64, dt.timedelta)):
+        value = Timedelta(value)
+
+    return value
+
+
+def maybe_box_native(value: Scalar | None | NAType) -> Scalar | None | NAType:
+    """
+    If passed a scalar cast the scalar to a python native type.
+
+    Parameters
+    ----------
+    value : scalar or Series
+
+    Returns
+    -------
+    scalar or Series
+    """
+    if is_float(value):
+        value = float(value)
+    elif is_integer(value):
+        value = int(value)
+    elif is_bool(value):
+        value = bool(value)
+    elif isinstance(value, (np.datetime64, np.timedelta64)):
+        value = maybe_box_datetimelike(value)
+    elif value is NA:
+        value = None
+    return value
+
+
+def _maybe_unbox_datetimelike(value: Scalar, dtype: DtypeObj) -> Scalar:
+    """
+    Convert a Timedelta or Timestamp to timedelta64 or datetime64 for setting
+    into a numpy array.  Failing to unbox would risk dropping nanoseconds.
+
+    Notes
+    -----
+    Caller is responsible for checking dtype.kind in "mM"
+    """
+    if is_valid_na_for_dtype(value, dtype):
+        # GH#36541: can't fill array directly with pd.NaT
+        # > np.empty(10, dtype="datetime64[ns]").fill(pd.NaT)
+        # ValueError: cannot convert float NaN to integer
+        value = dtype.type("NaT", "ns")
+    elif isinstance(value, Timestamp):
+        if value.tz is None:
+            value = value.to_datetime64()
+        elif not isinstance(dtype, DatetimeTZDtype):
+            raise TypeError("Cannot unbox tzaware Timestamp to tznaive dtype")
+    elif isinstance(value, Timedelta):
+        value = value.to_timedelta64()
+
+    _disallow_mismatched_datetimelike(value, dtype)
+    return value
+
+
+def _disallow_mismatched_datetimelike(value, dtype: DtypeObj):
+    """
+    numpy allows np.array(dt64values, dtype="timedelta64[ns]") and
+    vice-versa, but we do not want to allow this, so we need to
+    check explicitly
+    """
+    vdtype = getattr(value, "dtype", None)
+    if vdtype is None:
+        return
+    elif (vdtype.kind == "m" and dtype.kind == "M") or (
+        vdtype.kind == "M" and dtype.kind == "m"
+    ):
+        raise TypeError(f"Cannot cast {repr(value)} to {dtype}")
+
+
+@overload
+def maybe_downcast_to_dtype(result: np.ndarray, dtype: str | np.dtype) -> np.ndarray:
+    ...
+
+
+@overload
+def maybe_downcast_to_dtype(result: ExtensionArray, dtype: str | np.dtype) -> ArrayLike:
+    ...
+
+
+def maybe_downcast_to_dtype(result: ArrayLike, dtype: str | np.dtype) -> ArrayLike:
+    """
+    try to cast to the specified dtype (e.g. convert back to bool/int
+    or could be an astype of float64->float32
+    """
+    if isinstance(result, ABCSeries):
+        result = result._values
+    do_round = False
+
+    if isinstance(dtype, str):
+        if dtype == "infer":
+            inferred_type = lib.infer_dtype(result, skipna=False)
+            if inferred_type == "boolean":
+                dtype = "bool"
+            elif inferred_type == "integer":
+                dtype = "int64"
+            elif inferred_type == "datetime64":
+                dtype = "datetime64[ns]"
+            elif inferred_type in ["timedelta", "timedelta64"]:
+                dtype = "timedelta64[ns]"
+
+            # try to upcast here
+            elif inferred_type == "floating":
+                dtype = "int64"
+                if issubclass(result.dtype.type, np.number):
+                    do_round = True
+
+            else:
+                # TODO: complex?  what if result is already non-object?
+                dtype = "object"
+
+        dtype = np.dtype(dtype)
+
+    if not isinstance(dtype, np.dtype):
+        # enforce our signature annotation
+        raise TypeError(dtype)  # pragma: no cover
+
+    converted = maybe_downcast_numeric(result, dtype, do_round)
+    if converted is not result:
+        return converted
+
+    # a datetimelike
+    # GH12821, iNaT is cast to float
+    if dtype.kind in "mM" and result.dtype.kind in "if":
+        result = result.astype(dtype)
+
+    elif dtype.kind == "m" and result.dtype == _dtype_obj:
+        # test_where_downcast_to_td64
+        result = cast(np.ndarray, result)
+        result = array_to_timedelta64(result)
+
+    elif dtype == np.dtype("M8[ns]") and result.dtype == _dtype_obj:
+        result = cast(np.ndarray, result)
+        return np.asarray(maybe_cast_to_datetime(result, dtype=dtype))
+
+    return result
+
+
+@overload
+def maybe_downcast_numeric(
+    result: np.ndarray, dtype: np.dtype, do_round: bool = False
+) -> np.ndarray:
+    ...
+
+
+@overload
+def maybe_downcast_numeric(
+    result: ExtensionArray, dtype: DtypeObj, do_round: bool = False
+) -> ArrayLike:
+    ...
+
+
+def maybe_downcast_numeric(
+    result: ArrayLike, dtype: DtypeObj, do_round: bool = False
+) -> ArrayLike:
+    """
+    Subset of maybe_downcast_to_dtype restricted to numeric dtypes.
+
+    Parameters
+    ----------
+    result : ndarray or ExtensionArray
+    dtype : np.dtype or ExtensionDtype
+    do_round : bool
+
+    Returns
+    -------
+    ndarray or ExtensionArray
+    """
+    if not isinstance(dtype, np.dtype) or not isinstance(result.dtype, np.dtype):
+        # e.g. SparseDtype has no itemsize attr
+        return result
+
+    def trans(x):
+        if do_round:
+            return x.round()
+        return x
+
+    if dtype.kind == result.dtype.kind:
+        # don't allow upcasts here (except if empty)
+        if result.dtype.itemsize <= dtype.itemsize and result.size:
+            return result
+
+    if dtype.kind in "biu":
+        if not result.size:
+            # if we don't have any elements, just astype it
+            return trans(result).astype(dtype)
+
+        if isinstance(result, np.ndarray):
+            element = result.item(0)
+        else:
+            element = result.iloc[0]
+        if not isinstance(element, (np.integer, np.floating, int, float, bool)):
+            # a comparable, e.g. a Decimal may slip in here
+            return result
+
+        if (
+            issubclass(result.dtype.type, (np.object_, np.number))
+            and notna(result).all()
+        ):
+            new_result = trans(result).astype(dtype)
+            if new_result.dtype.kind == "O" or result.dtype.kind == "O":
+                # np.allclose may raise TypeError on object-dtype
+                if (new_result == result).all():
+                    return new_result
+            else:
+                if np.allclose(new_result, result, rtol=0):
+                    return new_result
+
+    elif (
+        issubclass(dtype.type, np.floating)
+        and result.dtype.kind != "b"
+        and not is_string_dtype(result.dtype)
+    ):
+        with warnings.catch_warnings():
+            warnings.filterwarnings(
+                "ignore", "overflow encountered in cast", RuntimeWarning
+            )
+            new_result = result.astype(dtype)
+
+        # Adjust tolerances based on floating point size
+        size_tols = {4: 5e-4, 8: 5e-8, 16: 5e-16}
+
+        atol = size_tols.get(new_result.dtype.itemsize, 0.0)
+
+        # Check downcast float values are still equal within 7 digits when
+        # converting from float64 to float32
+        if np.allclose(new_result, result, equal_nan=True, rtol=0.0, atol=atol):
+            return new_result
+
+    elif dtype.kind == result.dtype.kind == "c":
+        new_result = result.astype(dtype)
+
+        if np.array_equal(new_result, result, equal_nan=True):
+            # TODO: use tolerance like we do for float?
+            return new_result
+
+    return result
+
+
+def maybe_upcast_numeric_to_64bit(arr: NumpyIndexT) -> NumpyIndexT:
+    """
+    If array is a int/uint/float bit size lower than 64 bit, upcast it to 64 bit.
+
+    Parameters
+    ----------
+    arr : ndarray or ExtensionArray
+
+    Returns
+    -------
+    ndarray or ExtensionArray
+    """
+    dtype = arr.dtype
+    if dtype.kind == "i" and dtype != np.int64:
+        return arr.astype(np.int64)
+    elif dtype.kind == "u" and dtype != np.uint64:
+        return arr.astype(np.uint64)
+    elif dtype.kind == "f" and dtype != np.float64:
+        return arr.astype(np.float64)
+    else:
+        return arr
+
+
+def maybe_cast_pointwise_result(
+    result: ArrayLike,
+    dtype: DtypeObj,
+    numeric_only: bool = False,
+    same_dtype: bool = True,
+) -> ArrayLike:
+    """
+    Try casting result of a pointwise operation back to the original dtype if
+    appropriate.
+
+    Parameters
+    ----------
+    result : array-like
+        Result to cast.
+    dtype : np.dtype or ExtensionDtype
+        Input Series from which result was calculated.
+    numeric_only : bool, default False
+        Whether to cast only numerics or datetimes as well.
+    same_dtype : bool, default True
+        Specify dtype when calling _from_sequence
+
+    Returns
+    -------
+    result : array-like
+        result maybe casted to the dtype.
+    """
+
+    if isinstance(dtype, ExtensionDtype):
+        cls = dtype.construct_array_type()
+        if same_dtype:
+            result = _maybe_cast_to_extension_array(cls, result, dtype=dtype)
+        else:
+            result = _maybe_cast_to_extension_array(cls, result)
+
+    elif (numeric_only and dtype.kind in "iufcb") or not numeric_only:
+        result = maybe_downcast_to_dtype(result, dtype)
+
+    return result
+
+
+def _maybe_cast_to_extension_array(
+    cls: type[ExtensionArray], obj: ArrayLike, dtype: ExtensionDtype | None = None
+) -> ArrayLike:
+    """
+    Call to `_from_sequence` that returns the object unchanged on Exception.
+
+    Parameters
+    ----------
+    cls : class, subclass of ExtensionArray
+    obj : arraylike
+        Values to pass to cls._from_sequence
+    dtype : ExtensionDtype, optional
+
+    Returns
+    -------
+    ExtensionArray or obj
+    """
+    result: ArrayLike
+
+    if dtype is not None:
+        try:
+            result = cls._from_scalars(obj, dtype=dtype)
+        except (TypeError, ValueError):
+            return obj
+        return result
+
+    try:
+        result = cls._from_sequence(obj, dtype=dtype)
+    except Exception:
+        # We can't predict what downstream EA constructors may raise
+        result = obj
+    return result
+
+
+@overload
+def ensure_dtype_can_hold_na(dtype: np.dtype) -> np.dtype:
+    ...
+
+
+@overload
+def ensure_dtype_can_hold_na(dtype: ExtensionDtype) -> ExtensionDtype:
+    ...
+
+
+def ensure_dtype_can_hold_na(dtype: DtypeObj) -> DtypeObj:
+    """
+    If we have a dtype that cannot hold NA values, find the best match that can.
+    """
+    if isinstance(dtype, ExtensionDtype):
+        if dtype._can_hold_na:
+            return dtype
+        elif isinstance(dtype, IntervalDtype):
+            # TODO(GH#45349): don't special-case IntervalDtype, allow
+            #  overriding instead of returning object below.
+            return IntervalDtype(np.float64, closed=dtype.closed)
+        return _dtype_obj
+    elif dtype.kind == "b":
+        return _dtype_obj
+    elif dtype.kind in "iu":
+        return np.dtype(np.float64)
+    return dtype
+
+
+_canonical_nans = {
+    np.datetime64: np.datetime64("NaT", "ns"),
+    np.timedelta64: np.timedelta64("NaT", "ns"),
+    type(np.nan): np.nan,
+}
+
+
+def maybe_promote(dtype: np.dtype, fill_value=np.nan):
+    """
+    Find the minimal dtype that can hold both the given dtype and fill_value.
+
+    Parameters
+    ----------
+    dtype : np.dtype
+    fill_value : scalar, default np.nan
+
+    Returns
+    -------
+    dtype
+        Upcasted from dtype argument if necessary.
+    fill_value
+        Upcasted from fill_value argument if necessary.
+
+    Raises
+    ------
+    ValueError
+        If fill_value is a non-scalar and dtype is not object.
+    """
+    orig = fill_value
+    orig_is_nat = False
+    if checknull(fill_value):
+        # https://github.com/pandas-dev/pandas/pull/39692#issuecomment-1441051740
+        #  avoid cache misses with NaN/NaT values that are not singletons
+        if fill_value is not NA:
+            try:
+                orig_is_nat = np.isnat(fill_value)
+            except TypeError:
+                pass
+
+        fill_value = _canonical_nans.get(type(fill_value), fill_value)
+
+    # for performance, we are using a cached version of the actual implementation
+    # of the function in _maybe_promote. However, this doesn't always work (in case
+    # of non-hashable arguments), so we fallback to the actual implementation if needed
+    try:
+        # error: Argument 3 to "__call__" of "_lru_cache_wrapper" has incompatible type
+        # "Type[Any]"; expected "Hashable"  [arg-type]
+        dtype, fill_value = _maybe_promote_cached(
+            dtype, fill_value, type(fill_value)  # type: ignore[arg-type]
+        )
+    except TypeError:
+        # if fill_value is not hashable (required for caching)
+        dtype, fill_value = _maybe_promote(dtype, fill_value)
+
+    if (dtype == _dtype_obj and orig is not None) or (
+        orig_is_nat and np.datetime_data(orig)[0] != "ns"
+    ):
+        # GH#51592,53497 restore our potentially non-canonical fill_value
+        fill_value = orig
+    return dtype, fill_value
+
+
+@functools.lru_cache
+def _maybe_promote_cached(dtype, fill_value, fill_value_type):
+    # The cached version of _maybe_promote below
+    # This also use fill_value_type as (unused) argument to use this in the
+    # cache lookup -> to differentiate 1 and True
+    return _maybe_promote(dtype, fill_value)
+
+
+def _maybe_promote(dtype: np.dtype, fill_value=np.nan):
+    # The actual implementation of the function, use `maybe_promote` above for
+    # a cached version.
+    if not is_scalar(fill_value):
+        # with object dtype there is nothing to promote, and the user can
+        #  pass pretty much any weird fill_value they like
+        if dtype != object:
+            # with object dtype there is nothing to promote, and the user can
+            #  pass pretty much any weird fill_value they like
+            raise ValueError("fill_value must be a scalar")
+        dtype = _dtype_obj
+        return dtype, fill_value
+
+    if is_valid_na_for_dtype(fill_value, dtype) and dtype.kind in "iufcmM":
+        dtype = ensure_dtype_can_hold_na(dtype)
+        fv = na_value_for_dtype(dtype)
+        return dtype, fv
+
+    elif isinstance(dtype, CategoricalDtype):
+        if fill_value in dtype.categories or isna(fill_value):
+            return dtype, fill_value
+        else:
+            return object, ensure_object(fill_value)
+
+    elif isna(fill_value):
+        dtype = _dtype_obj
+        if fill_value is None:
+            # but we retain e.g. pd.NA
+            fill_value = np.nan
+        return dtype, fill_value
+
+    # returns tuple of (dtype, fill_value)
+    if issubclass(dtype.type, np.datetime64):
+        inferred, fv = infer_dtype_from_scalar(fill_value)
+        if inferred == dtype:
+            return dtype, fv
+
+        from pandas.core.arrays import DatetimeArray
+
+        dta = DatetimeArray._from_sequence([], dtype="M8[ns]")
+        try:
+            fv = dta._validate_setitem_value(fill_value)
+            return dta.dtype, fv
+        except (ValueError, TypeError):
+            return _dtype_obj, fill_value
+
+    elif issubclass(dtype.type, np.timedelta64):
+        inferred, fv = infer_dtype_from_scalar(fill_value)
+        if inferred == dtype:
+            return dtype, fv
+
+        elif inferred.kind == "m":
+            # different unit, e.g. passed np.timedelta64(24, "h") with dtype=m8[ns]
+            # see if we can losslessly cast it to our dtype
+            unit = np.datetime_data(dtype)[0]
+            try:
+                td = Timedelta(fill_value).as_unit(unit, round_ok=False)
+            except OutOfBoundsTimedelta:
+                return _dtype_obj, fill_value
+            else:
+                return dtype, td.asm8
+
+        return _dtype_obj, fill_value
+
+    elif is_float(fill_value):
+        if issubclass(dtype.type, np.bool_):
+            dtype = np.dtype(np.object_)
+
+        elif issubclass(dtype.type, np.integer):
+            dtype = np.dtype(np.float64)
+
+        elif dtype.kind == "f":
+            mst = np.min_scalar_type(fill_value)
+            if mst > dtype:
+                # e.g. mst is np.float64 and dtype is np.float32
+                dtype = mst
+
+        elif dtype.kind == "c":
+            mst = np.min_scalar_type(fill_value)
+            dtype = np.promote_types(dtype, mst)
+
+    elif is_bool(fill_value):
+        if not issubclass(dtype.type, np.bool_):
+            dtype = np.dtype(np.object_)
+
+    elif is_integer(fill_value):
+        if issubclass(dtype.type, np.bool_):
+            dtype = np.dtype(np.object_)
+
+        elif issubclass(dtype.type, np.integer):
+            if not np_can_cast_scalar(fill_value, dtype):  # type: ignore[arg-type]
+                # upcast to prevent overflow
+                mst = np.min_scalar_type(fill_value)
+                dtype = np.promote_types(dtype, mst)
+                if dtype.kind == "f":
+                    # Case where we disagree with numpy
+                    dtype = np.dtype(np.object_)
+
+    elif is_complex(fill_value):
+        if issubclass(dtype.type, np.bool_):
+            dtype = np.dtype(np.object_)
+
+        elif issubclass(dtype.type, (np.integer, np.floating)):
+            mst = np.min_scalar_type(fill_value)
+            dtype = np.promote_types(dtype, mst)
+
+        elif dtype.kind == "c":
+            mst = np.min_scalar_type(fill_value)
+            if mst > dtype:
+                # e.g. mst is np.complex128 and dtype is np.complex64
+                dtype = mst
+
+    else:
+        dtype = np.dtype(np.object_)
+
+    # in case we have a string that looked like a number
+    if issubclass(dtype.type, (bytes, str)):
+        dtype = np.dtype(np.object_)
+
+    fill_value = _ensure_dtype_type(fill_value, dtype)
+    return dtype, fill_value
+
+
+def _ensure_dtype_type(value, dtype: np.dtype):
+    """
+    Ensure that the given value is an instance of the given dtype.
+
+    e.g. if out dtype is np.complex64_, we should have an instance of that
+    as opposed to a python complex object.
+
+    Parameters
+    ----------
+    value : object
+    dtype : np.dtype
+
+    Returns
+    -------
+    object
+    """
+    # Start with exceptions in which we do _not_ cast to numpy types
+
+    if dtype == _dtype_obj:
+        return value
+
+    # Note: before we get here we have already excluded isna(value)
+    return dtype.type(value)
+
+
+def infer_dtype_from(val) -> tuple[DtypeObj, Any]:
+    """
+    Interpret the dtype from a scalar or array.
+
+    Parameters
+    ----------
+    val : object
+    """
+    if not is_list_like(val):
+        return infer_dtype_from_scalar(val)
+    return infer_dtype_from_array(val)
+
+
+def infer_dtype_from_scalar(val) -> tuple[DtypeObj, Any]:
+    """
+    Interpret the dtype from a scalar.
+
+    Parameters
+    ----------
+    val : object
+    """
+    dtype: DtypeObj = _dtype_obj
+
+    # a 1-element ndarray
+    if isinstance(val, np.ndarray):
+        if val.ndim != 0:
+            msg = "invalid ndarray passed to infer_dtype_from_scalar"
+            raise ValueError(msg)
+
+        dtype = val.dtype
+        val = lib.item_from_zerodim(val)
+
+    elif isinstance(val, str):
+        # If we create an empty array using a string to infer
+        # the dtype, NumPy will only allocate one character per entry
+        # so this is kind of bad. Alternately we could use np.repeat
+        # instead of np.empty (but then you still don't want things
+        # coming out as np.str_!
+
+        dtype = _dtype_obj
+        if using_pyarrow_string_dtype():
+            from pandas.core.arrays.string_ import StringDtype
+
+            dtype = StringDtype(storage="pyarrow_numpy")
+
+    elif isinstance(val, (np.datetime64, dt.datetime)):
+        try:
+            val = Timestamp(val)
+        except OutOfBoundsDatetime:
+            return _dtype_obj, val
+
+        if val is NaT or val.tz is None:
+            val = val.to_datetime64()
+            dtype = val.dtype
+            # TODO: test with datetime(2920, 10, 1) based on test_replace_dtypes
+        else:
+            dtype = DatetimeTZDtype(unit=val.unit, tz=val.tz)
+
+    elif isinstance(val, (np.timedelta64, dt.timedelta)):
+        try:
+            val = Timedelta(val)
+        except (OutOfBoundsTimedelta, OverflowError):
+            dtype = _dtype_obj
+        else:
+            if val is NaT:
+                val = np.timedelta64("NaT", "ns")
+            else:
+                val = val.asm8
+            dtype = val.dtype
+
+    elif is_bool(val):
+        dtype = np.dtype(np.bool_)
+
+    elif is_integer(val):
+        if isinstance(val, np.integer):
+            dtype = np.dtype(type(val))
+        else:
+            dtype = np.dtype(np.int64)
+
+        try:
+            np.array(val, dtype=dtype)
+        except OverflowError:
+            dtype = np.array(val).dtype
+
+    elif is_float(val):
+        if isinstance(val, np.floating):
+            dtype = np.dtype(type(val))
+        else:
+            dtype = np.dtype(np.float64)
+
+    elif is_complex(val):
+        dtype = np.dtype(np.complex128)
+
+    if isinstance(val, Period):
+        dtype = PeriodDtype(freq=val.freq)
+    elif isinstance(val, Interval):
+        subtype = infer_dtype_from_scalar(val.left)[0]
+        dtype = IntervalDtype(subtype=subtype, closed=val.closed)
+
+    return dtype, val
+
+
+def dict_compat(d: dict[Scalar, Scalar]) -> dict[Scalar, Scalar]:
+    """
+    Convert datetimelike-keyed dicts to a Timestamp-keyed dict.
+
+    Parameters
+    ----------
+    d: dict-like object
+
+    Returns
+    -------
+    dict
+    """
+    return {maybe_box_datetimelike(key): value for key, value in d.items()}
+
+
+def infer_dtype_from_array(arr) -> tuple[DtypeObj, ArrayLike]:
+    """
+    Infer the dtype from an array.
+
+    Parameters
+    ----------
+    arr : array
+
+    Returns
+    -------
+    tuple (pandas-compat dtype, array)
+
+
+    Examples
+    --------
+    >>> np.asarray([1, '1'])
+    array(['1', '1'], dtype='<U21')
+
+    >>> infer_dtype_from_array([1, '1'])
+    (dtype('O'), [1, '1'])
+    """
+    if isinstance(arr, np.ndarray):
+        return arr.dtype, arr
+
+    if not is_list_like(arr):
+        raise TypeError("'arr' must be list-like")
+
+    arr_dtype = getattr(arr, "dtype", None)
+    if isinstance(arr_dtype, ExtensionDtype):
+        return arr.dtype, arr
+
+    elif isinstance(arr, ABCSeries):
+        return arr.dtype, np.asarray(arr)
+
+    # don't force numpy coerce with nan's
+    inferred = lib.infer_dtype(arr, skipna=False)
+    if inferred in ["string", "bytes", "mixed", "mixed-integer"]:
+        return (np.dtype(np.object_), arr)
+
+    arr = np.asarray(arr)
+    return arr.dtype, arr
+
+
+def _maybe_infer_dtype_type(element):
+    """
+    Try to infer an object's dtype, for use in arithmetic ops.
+
+    Uses `element.dtype` if that's available.
+    Objects implementing the iterator protocol are cast to a NumPy array,
+    and from there the array's type is used.
+
+    Parameters
+    ----------
+    element : object
+        Possibly has a `.dtype` attribute, and possibly the iterator
+        protocol.
+
+    Returns
+    -------
+    tipo : type
+
+    Examples
+    --------
+    >>> from collections import namedtuple
+    >>> Foo = namedtuple("Foo", "dtype")
+    >>> _maybe_infer_dtype_type(Foo(np.dtype("i8")))
+    dtype('int64')
+    """
+    tipo = None
+    if hasattr(element, "dtype"):
+        tipo = element.dtype
+    elif is_list_like(element):
+        element = np.asarray(element)
+        tipo = element.dtype
+    return tipo
+
+
+def invalidate_string_dtypes(dtype_set: set[DtypeObj]) -> None:
+    """
+    Change string like dtypes to object for
+    ``DataFrame.select_dtypes()``.
+    """
+    # error: Argument 1 to <set> has incompatible type "Type[generic]"; expected
+    # "Union[dtype[Any], ExtensionDtype, None]"
+    # error: Argument 2 to <set> has incompatible type "Type[generic]"; expected
+    # "Union[dtype[Any], ExtensionDtype, None]"
+    non_string_dtypes = dtype_set - {
+        np.dtype("S").type,  # type: ignore[arg-type]
+        np.dtype("<U").type,  # type: ignore[arg-type]
+    }
+    if non_string_dtypes != dtype_set:
+        raise TypeError("string dtypes are not allowed, use 'object' instead")
+
+
+def coerce_indexer_dtype(indexer, categories) -> np.ndarray:
+    """coerce the indexer input array to the smallest dtype possible"""
+    length = len(categories)
+    if length < _int8_max:
+        return ensure_int8(indexer)
+    elif length < _int16_max:
+        return ensure_int16(indexer)
+    elif length < _int32_max:
+        return ensure_int32(indexer)
+    return ensure_int64(indexer)
+
+
+def convert_dtypes(
+    input_array: ArrayLike,
+    convert_string: bool = True,
+    convert_integer: bool = True,
+    convert_boolean: bool = True,
+    convert_floating: bool = True,
+    infer_objects: bool = False,
+    dtype_backend: Literal["numpy_nullable", "pyarrow"] = "numpy_nullable",
+) -> DtypeObj:
+    """
+    Convert objects to best possible type, and optionally,
+    to types supporting ``pd.NA``.
+
+    Parameters
+    ----------
+    input_array : ExtensionArray or np.ndarray
+    convert_string : bool, default True
+        Whether object dtypes should be converted to ``StringDtype()``.
+    convert_integer : bool, default True
+        Whether, if possible, conversion can be done to integer extension types.
+    convert_boolean : bool, defaults True
+        Whether object dtypes should be converted to ``BooleanDtypes()``.
+    convert_floating : bool, defaults True
+        Whether, if possible, conversion can be done to floating extension types.
+        If `convert_integer` is also True, preference will be give to integer
+        dtypes if the floats can be faithfully casted to integers.
+    infer_objects : bool, defaults False
+        Whether to also infer objects to float/int if possible. Is only hit if the
+        object array contains pd.NA.
+    dtype_backend : {'numpy_nullable', 'pyarrow'}, default 'numpy_nullable'
+        Back-end data type applied to the resultant :class:`DataFrame`
+        (still experimental). Behaviour is as follows:
+
+        * ``"numpy_nullable"``: returns nullable-dtype-backed :class:`DataFrame`
+          (default).
+        * ``"pyarrow"``: returns pyarrow-backed nullable :class:`ArrowDtype`
+          DataFrame.
+
+        .. versionadded:: 2.0
+
+    Returns
+    -------
+    np.dtype, or ExtensionDtype
+    """
+    inferred_dtype: str | DtypeObj
+
+    if (
+        convert_string or convert_integer or convert_boolean or convert_floating
+    ) and isinstance(input_array, np.ndarray):
+        if input_array.dtype == object:
+            inferred_dtype = lib.infer_dtype(input_array)
+        else:
+            inferred_dtype = input_array.dtype
+
+        if is_string_dtype(inferred_dtype):
+            if not convert_string or inferred_dtype == "bytes":
+                inferred_dtype = input_array.dtype
+            else:
+                inferred_dtype = pandas_dtype_func("string")
+
+        if convert_integer:
+            target_int_dtype = pandas_dtype_func("Int64")
+
+            if input_array.dtype.kind in "iu":
+                from pandas.core.arrays.integer import NUMPY_INT_TO_DTYPE
+
+                inferred_dtype = NUMPY_INT_TO_DTYPE.get(
+                    input_array.dtype, target_int_dtype
+                )
+            elif input_array.dtype.kind in "fcb":
+                # TODO: de-dup with maybe_cast_to_integer_array?
+                arr = input_array[notna(input_array)]
+                if (arr.astype(int) == arr).all():
+                    inferred_dtype = target_int_dtype
+                else:
+                    inferred_dtype = input_array.dtype
+            elif (
+                infer_objects
+                and input_array.dtype == object
+                and (isinstance(inferred_dtype, str) and inferred_dtype == "integer")
+            ):
+                inferred_dtype = target_int_dtype
+
+        if convert_floating:
+            if input_array.dtype.kind in "fcb":
+                # i.e. numeric but not integer
+                from pandas.core.arrays.floating import NUMPY_FLOAT_TO_DTYPE
+
+                inferred_float_dtype: DtypeObj = NUMPY_FLOAT_TO_DTYPE.get(
+                    input_array.dtype, pandas_dtype_func("Float64")
+                )
+                # if we could also convert to integer, check if all floats
+                # are actually integers
+                if convert_integer:
+                    # TODO: de-dup with maybe_cast_to_integer_array?
+                    arr = input_array[notna(input_array)]
+                    if (arr.astype(int) == arr).all():
+                        inferred_dtype = pandas_dtype_func("Int64")
+                    else:
+                        inferred_dtype = inferred_float_dtype
+                else:
+                    inferred_dtype = inferred_float_dtype
+            elif (
+                infer_objects
+                and input_array.dtype == object
+                and (
+                    isinstance(inferred_dtype, str)
+                    and inferred_dtype == "mixed-integer-float"
+                )
+            ):
+                inferred_dtype = pandas_dtype_func("Float64")
+
+        if convert_boolean:
+            if input_array.dtype.kind == "b":
+                inferred_dtype = pandas_dtype_func("boolean")
+            elif isinstance(inferred_dtype, str) and inferred_dtype == "boolean":
+                inferred_dtype = pandas_dtype_func("boolean")
+
+        if isinstance(inferred_dtype, str):
+            # If we couldn't do anything else, then we retain the dtype
+            inferred_dtype = input_array.dtype
+
+    else:
+        inferred_dtype = input_array.dtype
+
+    if dtype_backend == "pyarrow":
+        from pandas.core.arrays.arrow.array import to_pyarrow_type
+        from pandas.core.arrays.string_ import StringDtype
+
+        assert not isinstance(inferred_dtype, str)
+
+        if (
+            (convert_integer and inferred_dtype.kind in "iu")
+            or (convert_floating and inferred_dtype.kind in "fc")
+            or (convert_boolean and inferred_dtype.kind == "b")
+            or (convert_string and isinstance(inferred_dtype, StringDtype))
+            or (
+                inferred_dtype.kind not in "iufcb"
+                and not isinstance(inferred_dtype, StringDtype)
+            )
+        ):
+            if isinstance(inferred_dtype, PandasExtensionDtype) and not isinstance(
+                inferred_dtype, DatetimeTZDtype
+            ):
+                base_dtype = inferred_dtype.base
+            elif isinstance(inferred_dtype, (BaseMaskedDtype, ArrowDtype)):
+                base_dtype = inferred_dtype.numpy_dtype
+            elif isinstance(inferred_dtype, StringDtype):
+                base_dtype = np.dtype(str)
+            else:
+                base_dtype = inferred_dtype
+            if (
+                base_dtype.kind == "O"  # type: ignore[union-attr]
+                and input_array.size > 0
+                and isna(input_array).all()
+            ):
+                import pyarrow as pa
+
+                pa_type = pa.null()
+            else:
+                pa_type = to_pyarrow_type(base_dtype)
+            if pa_type is not None:
+                inferred_dtype = ArrowDtype(pa_type)
+    elif dtype_backend == "numpy_nullable" and isinstance(inferred_dtype, ArrowDtype):
+        # GH 53648
+        inferred_dtype = _arrow_dtype_mapping()[inferred_dtype.pyarrow_dtype]
+
+    # error: Incompatible return value type (got "Union[str, Union[dtype[Any],
+    # ExtensionDtype]]", expected "Union[dtype[Any], ExtensionDtype]")
+    return inferred_dtype  # type: ignore[return-value]
+
+
+def maybe_infer_to_datetimelike(
+    value: npt.NDArray[np.object_],
+) -> np.ndarray | DatetimeArray | TimedeltaArray | PeriodArray | IntervalArray:
+    """
+    we might have a array (or single object) that is datetime like,
+    and no dtype is passed don't change the value unless we find a
+    datetime/timedelta set
+
+    this is pretty strict in that a datetime/timedelta is REQUIRED
+    in addition to possible nulls/string likes
+
+    Parameters
+    ----------
+    value : np.ndarray[object]
+
+    Returns
+    -------
+    np.ndarray, DatetimeArray, TimedeltaArray, PeriodArray, or IntervalArray
+
+    """
+    if not isinstance(value, np.ndarray) or value.dtype != object:
+        # Caller is responsible for passing only ndarray[object]
+        raise TypeError(type(value))  # pragma: no cover
+    if value.ndim != 1:
+        # Caller is responsible
+        raise ValueError(value.ndim)  # pragma: no cover
+
+    if not len(value):
+        return value
+
+    # error: Incompatible return value type (got "Union[ExtensionArray,
+    # ndarray[Any, Any]]", expected "Union[ndarray[Any, Any], DatetimeArray,
+    # TimedeltaArray, PeriodArray, IntervalArray]")
+    return lib.maybe_convert_objects(  # type: ignore[return-value]
+        value,
+        # Here we do not convert numeric dtypes, as if we wanted that,
+        #  numpy would have done it for us.
+        convert_numeric=False,
+        convert_non_numeric=True,
+        dtype_if_all_nat=np.dtype("M8[ns]"),
+    )
+
+
+def maybe_cast_to_datetime(
+    value: np.ndarray | list, dtype: np.dtype
+) -> ExtensionArray | np.ndarray:
+    """
+    try to cast the array/value to a datetimelike dtype, converting float
+    nan to iNaT
+
+    Caller is responsible for handling ExtensionDtype cases and non dt64/td64
+    cases.
+    """
+    from pandas.core.arrays.datetimes import DatetimeArray
+    from pandas.core.arrays.timedeltas import TimedeltaArray
+
+    assert dtype.kind in "mM"
+    if not is_list_like(value):
+        raise TypeError("value must be listlike")
+
+    # TODO: _from_sequence would raise ValueError in cases where
+    #  _ensure_nanosecond_dtype raises TypeError
+    _ensure_nanosecond_dtype(dtype)
+
+    if lib.is_np_dtype(dtype, "m"):
+        res = TimedeltaArray._from_sequence(value, dtype=dtype)
+        return res
+    else:
+        try:
+            dta = DatetimeArray._from_sequence(value, dtype=dtype)
+        except ValueError as err:
+            # We can give a Series-specific exception message.
+            if "cannot supply both a tz and a timezone-naive dtype" in str(err):
+                raise ValueError(
+                    "Cannot convert timezone-aware data to "
+                    "timezone-naive dtype. Use "
+                    "pd.Series(values).dt.tz_localize(None) instead."
+                ) from err
+            raise
+
+        return dta
+
+
+def _ensure_nanosecond_dtype(dtype: DtypeObj) -> None:
+    """
+    Convert dtypes with granularity less than nanosecond to nanosecond
+
+    >>> _ensure_nanosecond_dtype(np.dtype("M8[us]"))
+
+    >>> _ensure_nanosecond_dtype(np.dtype("M8[D]"))
+    Traceback (most recent call last):
+        ...
+    TypeError: dtype=datetime64[D] is not supported. Supported resolutions are 's', 'ms', 'us', and 'ns'
+
+    >>> _ensure_nanosecond_dtype(np.dtype("m8[ps]"))
+    Traceback (most recent call last):
+        ...
+    TypeError: dtype=timedelta64[ps] is not supported. Supported resolutions are 's', 'ms', 'us', and 'ns'
+    """  # noqa: E501
+    msg = (
+        f"The '{dtype.name}' dtype has no unit. "
+        f"Please pass in '{dtype.name}[ns]' instead."
+    )
+
+    # unpack e.g. SparseDtype
+    dtype = getattr(dtype, "subtype", dtype)
+
+    if not isinstance(dtype, np.dtype):
+        # i.e. datetime64tz
+        pass
+
+    elif dtype.kind in "mM":
+        if not is_supported_dtype(dtype):
+            # pre-2.0 we would silently swap in nanos for lower-resolutions,
+            #  raise for above-nano resolutions
+            if dtype.name in ["datetime64", "timedelta64"]:
+                raise ValueError(msg)
+            # TODO: ValueError or TypeError? existing test
+            #  test_constructor_generic_timestamp_bad_frequency expects TypeError
+            raise TypeError(
+                f"dtype={dtype} is not supported. Supported resolutions are 's', "
+                "'ms', 'us', and 'ns'"
+            )
+
+
+# TODO: other value-dependent functions to standardize here include
+#  Index._find_common_type_compat
+def find_result_type(left_dtype: DtypeObj, right: Any) -> DtypeObj:
+    """
+    Find the type/dtype for the result of an operation between objects.
+
+    This is similar to find_common_type, but looks at the right object instead
+    of just its dtype. This can be useful in particular when the right
+    object does not have a `dtype`.
+
+    Parameters
+    ----------
+    left_dtype : np.dtype or ExtensionDtype
+    right : Any
+
+    Returns
+    -------
+    np.dtype or ExtensionDtype
+
+    See also
+    --------
+    find_common_type
+    numpy.result_type
+    """
+    new_dtype: DtypeObj
+
+    if (
+        isinstance(left_dtype, np.dtype)
+        and left_dtype.kind in "iuc"
+        and (lib.is_integer(right) or lib.is_float(right))
+    ):
+        # e.g. with int8 dtype and right=512, we want to end up with
+        # np.int16, whereas infer_dtype_from(512) gives np.int64,
+        #  which will make us upcast too far.
+        if lib.is_float(right) and right.is_integer() and left_dtype.kind != "f":
+            right = int(right)
+        # After NEP 50, numpy won't inspect Python scalars
+        # TODO: do we need to recreate numpy's inspection logic for floats too
+        # (this breaks some tests)
+        if isinstance(right, int) and not isinstance(right, np.integer):
+            # This gives an unsigned type by default
+            # (if our number is positive)
+
+            # If our left dtype is signed, we might not want this since
+            # this might give us 1 dtype too big
+            # We should check if the corresponding int dtype (e.g. int64 for uint64)
+            # can hold the number
+            right_dtype = np.min_scalar_type(right)
+            if right == 0:
+                # Special case 0
+                right = left_dtype
+            elif (
+                not np.issubdtype(left_dtype, np.unsignedinteger)
+                and 0 < right <= np.iinfo(right_dtype).max
+            ):
+                # If left dtype isn't unsigned, check if it fits in the signed dtype
+                right = np.dtype(f"i{right_dtype.itemsize}")
+            else:
+                right = right_dtype
+
+        new_dtype = np.result_type(left_dtype, right)
+
+    elif is_valid_na_for_dtype(right, left_dtype):
+        # e.g. IntervalDtype[int] and None/np.nan
+        new_dtype = ensure_dtype_can_hold_na(left_dtype)
+
+    else:
+        dtype, _ = infer_dtype_from(right)
+        new_dtype = find_common_type([left_dtype, dtype])
+
+    return new_dtype
+
+
+def common_dtype_categorical_compat(
+    objs: Sequence[Index | ArrayLike], dtype: DtypeObj
+) -> DtypeObj:
+    """
+    Update the result of find_common_type to account for NAs in a Categorical.
+
+    Parameters
+    ----------
+    objs : list[np.ndarray | ExtensionArray | Index]
+    dtype : np.dtype or ExtensionDtype
+
+    Returns
+    -------
+    np.dtype or ExtensionDtype
+    """
+    # GH#38240
+
+    # TODO: more generally, could do `not can_hold_na(dtype)`
+    if lib.is_np_dtype(dtype, "iu"):
+        for obj in objs:
+            # We don't want to accientally allow e.g. "categorical" str here
+            obj_dtype = getattr(obj, "dtype", None)
+            if isinstance(obj_dtype, CategoricalDtype):
+                if isinstance(obj, ABCIndex):
+                    # This check may already be cached
+                    hasnas = obj.hasnans
+                else:
+                    # Categorical
+                    hasnas = cast("Categorical", obj)._hasna
+
+                if hasnas:
+                    # see test_union_int_categorical_with_nan
+                    dtype = np.dtype(np.float64)
+                    break
+    return dtype
+
+
+def np_find_common_type(*dtypes: np.dtype) -> np.dtype:
+    """
+    np.find_common_type implementation pre-1.25 deprecation using np.result_type
+    https://github.com/pandas-dev/pandas/pull/49569#issuecomment-1308300065
+
+    Parameters
+    ----------
+    dtypes : np.dtypes
+
+    Returns
+    -------
+    np.dtype
+    """
+    try:
+        common_dtype = np.result_type(*dtypes)
+        if common_dtype.kind in "mMSU":
+            # NumPy promotion currently (1.25) misbehaves for for times and strings,
+            # so fall back to object (find_common_dtype did unless there
+            # was only one dtype)
+            common_dtype = np.dtype("O")
+
+    except TypeError:
+        common_dtype = np.dtype("O")
+    return common_dtype
+
+
+@overload
+def find_common_type(types: list[np.dtype]) -> np.dtype:
+    ...
+
+
+@overload
+def find_common_type(types: list[ExtensionDtype]) -> DtypeObj:
+    ...
+
+
+@overload
+def find_common_type(types: list[DtypeObj]) -> DtypeObj:
+    ...
+
+
+def find_common_type(types):
+    """
+    Find a common data type among the given dtypes.
+
+    Parameters
+    ----------
+    types : list of dtypes
+
+    Returns
+    -------
+    pandas extension or numpy dtype
+
+    See Also
+    --------
+    numpy.find_common_type
+
+    """
+    if not types:
+        raise ValueError("no types given")
+
+    first = types[0]
+
+    # workaround for find_common_type([np.dtype('datetime64[ns]')] * 2)
+    # => object
+    if lib.dtypes_all_equal(list(types)):
+        return first
+
+    # get unique types (dict.fromkeys is used as order-preserving set())
+    types = list(dict.fromkeys(types).keys())
+
+    if any(isinstance(t, ExtensionDtype) for t in types):
+        for t in types:
+            if isinstance(t, ExtensionDtype):
+                res = t._get_common_dtype(types)
+                if res is not None:
+                    return res
+        return np.dtype("object")
+
+    # take lowest unit
+    if all(lib.is_np_dtype(t, "M") for t in types):
+        return np.dtype(max(types))
+    if all(lib.is_np_dtype(t, "m") for t in types):
+        return np.dtype(max(types))
+
+    # don't mix bool / int or float or complex
+    # this is different from numpy, which casts bool with float/int as int
+    has_bools = any(t.kind == "b" for t in types)
+    if has_bools:
+        for t in types:
+            if t.kind in "iufc":
+                return np.dtype("object")
+
+    return np_find_common_type(*types)
+
+
+def construct_2d_arraylike_from_scalar(
+    value: Scalar, length: int, width: int, dtype: np.dtype, copy: bool
+) -> np.ndarray:
+    shape = (length, width)
+
+    if dtype.kind in "mM":
+        value = _maybe_box_and_unbox_datetimelike(value, dtype)
+    elif dtype == _dtype_obj:
+        if isinstance(value, (np.timedelta64, np.datetime64)):
+            # calling np.array below would cast to pytimedelta/pydatetime
+            out = np.empty(shape, dtype=object)
+            out.fill(value)
+            return out
+
+    # Attempt to coerce to a numpy array
+    try:
+        if not copy:
+            arr = np.asarray(value, dtype=dtype)
+        else:
+            arr = np.array(value, dtype=dtype, copy=copy)
+    except (ValueError, TypeError) as err:
+        raise TypeError(
+            f"DataFrame constructor called with incompatible data and dtype: {err}"
+        ) from err
+
+    if arr.ndim != 0:
+        raise ValueError("DataFrame constructor not properly called!")
+
+    return np.full(shape, arr)
+
+
+def construct_1d_arraylike_from_scalar(
+    value: Scalar, length: int, dtype: DtypeObj | None
+) -> ArrayLike:
+    """
+    create a np.ndarray / pandas type of specified shape and dtype
+    filled with values
+
+    Parameters
+    ----------
+    value : scalar value
+    length : int
+    dtype : pandas_dtype or np.dtype
+
+    Returns
+    -------
+    np.ndarray / pandas type of length, filled with value
+
+    """
+
+    if dtype is None:
+        try:
+            dtype, value = infer_dtype_from_scalar(value)
+        except OutOfBoundsDatetime:
+            dtype = _dtype_obj
+
+    if isinstance(dtype, ExtensionDtype):
+        cls = dtype.construct_array_type()
+        seq = [] if length == 0 else [value]
+        subarr = cls._from_sequence(seq, dtype=dtype).repeat(length)
+
+    else:
+        if length and dtype.kind in "iu" and isna(value):
+            # coerce if we have nan for an integer dtype
+            dtype = np.dtype("float64")
+        elif lib.is_np_dtype(dtype, "US"):
+            # we need to coerce to object dtype to avoid
+            # to allow numpy to take our string as a scalar value
+            dtype = np.dtype("object")
+            if not isna(value):
+                value = ensure_str(value)
+        elif dtype.kind in "mM":
+            value = _maybe_box_and_unbox_datetimelike(value, dtype)
+
+        subarr = np.empty(length, dtype=dtype)
+        if length:
+            # GH 47391: numpy > 1.24 will raise filling np.nan into int dtypes
+            subarr.fill(value)
+
+    return subarr
+
+
+def _maybe_box_and_unbox_datetimelike(value: Scalar, dtype: DtypeObj):
+    # Caller is responsible for checking dtype.kind in "mM"
+
+    if isinstance(value, dt.datetime):
+        # we dont want to box dt64, in particular datetime64("NaT")
+        value = maybe_box_datetimelike(value, dtype)
+
+    return _maybe_unbox_datetimelike(value, dtype)
+
+
+def construct_1d_object_array_from_listlike(values: Sized) -> np.ndarray:
+    """
+    Transform any list-like object in a 1-dimensional numpy array of object
+    dtype.
+
+    Parameters
+    ----------
+    values : any iterable which has a len()
+
+    Raises
+    ------
+    TypeError
+        * If `values` does not have a len()
+
+    Returns
+    -------
+    1-dimensional numpy array of dtype object
+    """
+    # numpy will try to interpret nested lists as further dimensions, hence
+    # making a 1D array that contains list-likes is a bit tricky:
+    result = np.empty(len(values), dtype="object")
+    result[:] = values
+    return result
+
+
+def maybe_cast_to_integer_array(arr: list | np.ndarray, dtype: np.dtype) -> np.ndarray:
+    """
+    Takes any dtype and returns the casted version, raising for when data is
+    incompatible with integer/unsigned integer dtypes.
+
+    Parameters
+    ----------
+    arr : np.ndarray or list
+        The array to cast.
+    dtype : np.dtype
+        The integer dtype to cast the array to.
+
+    Returns
+    -------
+    ndarray
+        Array of integer or unsigned integer dtype.
+
+    Raises
+    ------
+    OverflowError : the dtype is incompatible with the data
+    ValueError : loss of precision has occurred during casting
+
+    Examples
+    --------
+    If you try to coerce negative values to unsigned integers, it raises:
+
+    >>> pd.Series([-1], dtype="uint64")
+    Traceback (most recent call last):
+        ...
+    OverflowError: Trying to coerce negative values to unsigned integers
+
+    Also, if you try to coerce float values to integers, it raises:
+
+    >>> maybe_cast_to_integer_array([1, 2, 3.5], dtype=np.dtype("int64"))
+    Traceback (most recent call last):
+        ...
+    ValueError: Trying to coerce float values to integers
+    """
+    assert dtype.kind in "iu"
+
+    try:
+        if not isinstance(arr, np.ndarray):
+            with warnings.catch_warnings():
+                # We already disallow dtype=uint w/ negative numbers
+                # (test_constructor_coercion_signed_to_unsigned) so safe to ignore.
+                if not np_version_gt2:
+                    warnings.filterwarnings(
+                        "ignore",
+                        "NumPy will stop allowing conversion of "
+                        "out-of-bound Python int",
+                        DeprecationWarning,
+                    )
+                casted = np.asarray(arr, dtype=dtype)
+        else:
+            with warnings.catch_warnings():
+                warnings.filterwarnings("ignore", category=RuntimeWarning)
+                casted = arr.astype(dtype, copy=False)
+    except OverflowError as err:
+        raise OverflowError(
+            "The elements provided in the data cannot all be "
+            f"casted to the dtype {dtype}"
+        ) from err
+
+    if isinstance(arr, np.ndarray) and arr.dtype == dtype:
+        # avoid expensive array_equal check
+        return casted
+
+    with warnings.catch_warnings():
+        warnings.filterwarnings("ignore", category=RuntimeWarning)
+        warnings.filterwarnings(
+            "ignore", "elementwise comparison failed", FutureWarning
+        )
+        if np.array_equal(arr, casted):
+            return casted
+
+    # We do this casting to allow for proper
+    # data and dtype checking.
+    #
+    # We didn't do this earlier because NumPy
+    # doesn't handle `uint64` correctly.
+    arr = np.asarray(arr)
+
+    if np.issubdtype(arr.dtype, str):
+        # TODO(numpy-2.0 min): This case will raise an OverflowError above
+        if (casted.astype(str) == arr).all():
+            return casted
+        raise ValueError(f"string values cannot be losslessly cast to {dtype}")
+
+    if dtype.kind == "u" and (arr < 0).any():
+        # TODO: can this be hit anymore after numpy 2.0?
+        raise OverflowError("Trying to coerce negative values to unsigned integers")
+
+    if arr.dtype.kind == "f":
+        if not np.isfinite(arr).all():
+            raise IntCastingNaNError(
+                "Cannot convert non-finite values (NA or inf) to integer"
+            )
+        raise ValueError("Trying to coerce float values to integers")
+    if arr.dtype == object:
+        raise ValueError("Trying to coerce float values to integers")
+
+    if casted.dtype < arr.dtype:
+        # TODO: Can this path be hit anymore with numpy > 2
+        # GH#41734 e.g. [1, 200, 923442] and dtype="int8" -> overflows
+        raise ValueError(
+            f"Values are too large to be losslessly converted to {dtype}. "
+            f"To cast anyway, use pd.Series(values).astype({dtype})"
+        )
+
+    if arr.dtype.kind in "mM":
+        # test_constructor_maskedarray_nonfloat
+        raise TypeError(
+            f"Constructing a Series or DataFrame from {arr.dtype} values and "
+            f"dtype={dtype} is not supported. Use values.view({dtype}) instead."
+        )
+
+    # No known cases that get here, but raising explicitly to cover our bases.
+    raise ValueError(f"values cannot be losslessly cast to {dtype}")
+
+
+def can_hold_element(arr: ArrayLike, element: Any) -> bool:
+    """
+    Can we do an inplace setitem with this element in an array with this dtype?
+
+    Parameters
+    ----------
+    arr : np.ndarray or ExtensionArray
+    element : Any
+
+    Returns
+    -------
+    bool
+    """
+    dtype = arr.dtype
+    if not isinstance(dtype, np.dtype) or dtype.kind in "mM":
+        if isinstance(dtype, (PeriodDtype, IntervalDtype, DatetimeTZDtype, np.dtype)):
+            # np.dtype here catches datetime64ns and timedelta64ns; we assume
+            #  in this case that we have DatetimeArray/TimedeltaArray
+            arr = cast(
+                "PeriodArray | DatetimeArray | TimedeltaArray | IntervalArray", arr
+            )
+            try:
+                arr._validate_setitem_value(element)
+                return True
+            except (ValueError, TypeError):
+                return False
+
+        # This is technically incorrect, but maintains the behavior of
+        # ExtensionBlock._can_hold_element
+        return True
+
+    try:
+        np_can_hold_element(dtype, element)
+        return True
+    except (TypeError, LossySetitemError):
+        return False
+
+
+def np_can_hold_element(dtype: np.dtype, element: Any) -> Any:
+    """
+    Raise if we cannot losslessly set this element into an ndarray with this dtype.
+
+    Specifically about places where we disagree with numpy.  i.e. there are
+    cases where numpy will raise in doing the setitem that we do not check
+    for here, e.g. setting str "X" into a numeric ndarray.
+
+    Returns
+    -------
+    Any
+        The element, potentially cast to the dtype.
+
+    Raises
+    ------
+    ValueError : If we cannot losslessly store this element with this dtype.
+    """
+    if dtype == _dtype_obj:
+        return element
+
+    tipo = _maybe_infer_dtype_type(element)
+
+    if dtype.kind in "iu":
+        if isinstance(element, range):
+            if _dtype_can_hold_range(element, dtype):
+                return element
+            raise LossySetitemError
+
+        if is_integer(element) or (is_float(element) and element.is_integer()):
+            # e.g. test_setitem_series_int8 if we have a python int 1
+            #  tipo may be np.int32, despite the fact that it will fit
+            #  in smaller int dtypes.
+            info = np.iinfo(dtype)
+            if info.min <= element <= info.max:
+                return dtype.type(element)
+            raise LossySetitemError
+
+        if tipo is not None:
+            if tipo.kind not in "iu":
+                if isinstance(element, np.ndarray) and element.dtype.kind == "f":
+                    # If all can be losslessly cast to integers, then we can hold them
+                    with np.errstate(invalid="ignore"):
+                        # We check afterwards if cast was losslessly, so no need to show
+                        # the warning
+                        casted = element.astype(dtype)
+                    comp = casted == element
+                    if comp.all():
+                        # Return the casted values bc they can be passed to
+                        #  np.putmask, whereas the raw values cannot.
+                        #  see TestSetitemFloatNDarrayIntoIntegerSeries
+                        return casted
+                    raise LossySetitemError
+
+                elif isinstance(element, ABCExtensionArray) and isinstance(
+                    element.dtype, CategoricalDtype
+                ):
+                    # GH#52927 setting Categorical value into non-EA frame
+                    # TODO: general-case for EAs?
+                    try:
+                        casted = element.astype(dtype)
+                    except (ValueError, TypeError):
+                        raise LossySetitemError
+                    # Check for cases of either
+                    #  a) lossy overflow/rounding or
+                    #  b) semantic changes like dt64->int64
+                    comp = casted == element
+                    if not comp.all():
+                        raise LossySetitemError
+                    return casted
+
+                # Anything other than integer we cannot hold
+                raise LossySetitemError
+            if (
+                dtype.kind == "u"
+                and isinstance(element, np.ndarray)
+                and element.dtype.kind == "i"
+            ):
+                # see test_where_uint64
+                casted = element.astype(dtype)
+                if (casted == element).all():
+                    # TODO: faster to check (element >=0).all()?  potential
+                    #  itemsize issues there?
+                    return casted
+                raise LossySetitemError
+            if dtype.itemsize < tipo.itemsize:
+                raise LossySetitemError
+            if not isinstance(tipo, np.dtype):
+                # i.e. nullable IntegerDtype; we can put this into an ndarray
+                #  losslessly iff it has no NAs
+                arr = element._values if isinstance(element, ABCSeries) else element
+                if arr._hasna:
+                    raise LossySetitemError
+                return element
+
+            return element
+
+        raise LossySetitemError
+
+    if dtype.kind == "f":
+        if lib.is_integer(element) or lib.is_float(element):
+            casted = dtype.type(element)
+            if np.isnan(casted) or casted == element:
+                return casted
+            # otherwise e.g. overflow see TestCoercionFloat32
+            raise LossySetitemError
+
+        if tipo is not None:
+            # TODO: itemsize check?
+            if tipo.kind not in "iuf":
+                # Anything other than float/integer we cannot hold
+                raise LossySetitemError
+            if not isinstance(tipo, np.dtype):
+                # i.e. nullable IntegerDtype or FloatingDtype;
+                #  we can put this into an ndarray losslessly iff it has no NAs
+                if element._hasna:
+                    raise LossySetitemError
+                return element
+            elif tipo.itemsize > dtype.itemsize or tipo.kind != dtype.kind:
+                if isinstance(element, np.ndarray):
+                    # e.g. TestDataFrameIndexingWhere::test_where_alignment
+                    casted = element.astype(dtype)
+                    if np.array_equal(casted, element, equal_nan=True):
+                        return casted
+                    raise LossySetitemError
+
+            return element
+
+        raise LossySetitemError
+
+    if dtype.kind == "c":
+        if lib.is_integer(element) or lib.is_complex(element) or lib.is_float(element):
+            if np.isnan(element):
+                # see test_where_complex GH#6345
+                return dtype.type(element)
+
+            with warnings.catch_warnings():
+                warnings.filterwarnings("ignore")
+                casted = dtype.type(element)
+            if casted == element:
+                return casted
+            # otherwise e.g. overflow see test_32878_complex_itemsize
+            raise LossySetitemError
+
+        if tipo is not None:
+            if tipo.kind in "iufc":
+                return element
+            raise LossySetitemError
+        raise LossySetitemError
+
+    if dtype.kind == "b":
+        if tipo is not None:
+            if tipo.kind == "b":
+                if not isinstance(tipo, np.dtype):
+                    # i.e. we have a BooleanArray
+                    if element._hasna:
+                        # i.e. there are pd.NA elements
+                        raise LossySetitemError
+                return element
+            raise LossySetitemError
+        if lib.is_bool(element):
+            return element
+        raise LossySetitemError
+
+    if dtype.kind == "S":
+        # TODO: test tests.frame.methods.test_replace tests get here,
+        #  need more targeted tests.  xref phofl has a PR about this
+        if tipo is not None:
+            if tipo.kind == "S" and tipo.itemsize <= dtype.itemsize:
+                return element
+            raise LossySetitemError
+        if isinstance(element, bytes) and len(element) <= dtype.itemsize:
+            return element
+        raise LossySetitemError
+
+    if dtype.kind == "V":
+        # i.e. np.void, which cannot hold _anything_
+        raise LossySetitemError
+
+    raise NotImplementedError(dtype)
+
+
+def _dtype_can_hold_range(rng: range, dtype: np.dtype) -> bool:
+    """
+    _maybe_infer_dtype_type infers to int64 (and float64 for very large endpoints),
+    but in many cases a range can be held by a smaller integer dtype.
+    Check if this is one of those cases.
+    """
+    if not len(rng):
+        return True
+    return np_can_cast_scalar(rng.start, dtype) and np_can_cast_scalar(rng.stop, dtype)
+
+
+def np_can_cast_scalar(element: Scalar, dtype: np.dtype) -> bool:
+    """
+    np.can_cast pandas-equivalent for pre 2-0 behavior that allowed scalar
+    inference
+
+    Parameters
+    ----------
+    element : Scalar
+    dtype : np.dtype
+
+    Returns
+    -------
+    bool
+    """
+    try:
+        np_can_hold_element(dtype, element)
+        return True
+    except (LossySetitemError, NotImplementedError):
+        return False

venv/lib/python3.10/site-packages/pandas/core/internals/__init__.py

@@ -0,0 +1,85 @@
+from pandas.core.internals.api import make_block  # 2023-09-18 pyarrow uses this
+from pandas.core.internals.array_manager import (
+    ArrayManager,
+    SingleArrayManager,
+)
+from pandas.core.internals.base import (
+    DataManager,
+    SingleDataManager,
+)
+from pandas.core.internals.concat import concatenate_managers
+from pandas.core.internals.managers import (
+    BlockManager,
+    SingleBlockManager,
+)
+
+__all__ = [
+    "Block",  # pylint: disable=undefined-all-variable
+    "DatetimeTZBlock",  # pylint: disable=undefined-all-variable
+    "ExtensionBlock",  # pylint: disable=undefined-all-variable
+    "make_block",
+    "DataManager",
+    "ArrayManager",
+    "BlockManager",
+    "SingleDataManager",
+    "SingleBlockManager",
+    "SingleArrayManager",
+    "concatenate_managers",
+]
+
+
+def __getattr__(name: str):
+    # GH#55139
+    import warnings
+
+    if name == "create_block_manager_from_blocks":
+        # GH#33892
+        warnings.warn(
+            f"{name} is deprecated and will be removed in a future version. "
+            "Use public APIs instead.",
+            DeprecationWarning,
+            # https://github.com/pandas-dev/pandas/pull/55139#pullrequestreview-1720690758
+            # on hard-coding stacklevel
+            stacklevel=2,
+        )
+        from pandas.core.internals.managers import create_block_manager_from_blocks
+
+        return create_block_manager_from_blocks
+
+    if name in [
+        "NumericBlock",
+        "ObjectBlock",
+        "Block",
+        "ExtensionBlock",
+        "DatetimeTZBlock",
+    ]:
+        warnings.warn(
+            f"{name} is deprecated and will be removed in a future version. "
+            "Use public APIs instead.",
+            DeprecationWarning,
+            # https://github.com/pandas-dev/pandas/pull/55139#pullrequestreview-1720690758
+            # on hard-coding stacklevel
+            stacklevel=2,
+        )
+        if name == "NumericBlock":
+            from pandas.core.internals.blocks import NumericBlock
+
+            return NumericBlock
+        elif name == "DatetimeTZBlock":
+            from pandas.core.internals.blocks import DatetimeTZBlock
+
+            return DatetimeTZBlock
+        elif name == "ExtensionBlock":
+            from pandas.core.internals.blocks import ExtensionBlock
+
+            return ExtensionBlock
+        elif name == "Block":
+            from pandas.core.internals.blocks import Block
+
+            return Block
+        else:
+            from pandas.core.internals.blocks import ObjectBlock
+
+            return ObjectBlock
+
+    raise AttributeError(f"module 'pandas.core.internals' has no attribute '{name}'")

venv/lib/python3.10/site-packages/pandas/core/internals/api.py

@@ -0,0 +1,156 @@
+"""
+This is a pseudo-public API for downstream libraries.  We ask that downstream
+authors
+
+1) Try to avoid using internals directly altogether, and failing that,
+2) Use only functions exposed here (or in core.internals)
+
+"""
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import numpy as np
+
+from pandas._libs.internals import BlockPlacement
+
+from pandas.core.dtypes.common import pandas_dtype
+from pandas.core.dtypes.dtypes import (
+    DatetimeTZDtype,
+    PeriodDtype,
+)
+
+from pandas.core.arrays import DatetimeArray
+from pandas.core.construction import extract_array
+from pandas.core.internals.blocks import (
+    check_ndim,
+    ensure_block_shape,
+    extract_pandas_array,
+    get_block_type,
+    maybe_coerce_values,
+)
+
+if TYPE_CHECKING:
+    from pandas._typing import Dtype
+
+    from pandas.core.internals.blocks import Block
+
+
+def make_block(
+    values, placement, klass=None, ndim=None, dtype: Dtype | None = None
+) -> Block:
+    """
+    This is a pseudo-public analogue to blocks.new_block.
+
+    We ask that downstream libraries use this rather than any fully-internal
+    APIs, including but not limited to:
+
+    - core.internals.blocks.make_block
+    - Block.make_block
+    - Block.make_block_same_class
+    - Block.__init__
+    """
+    if dtype is not None:
+        dtype = pandas_dtype(dtype)
+
+    values, dtype = extract_pandas_array(values, dtype, ndim)
+
+    from pandas.core.internals.blocks import (
+        DatetimeTZBlock,
+        ExtensionBlock,
+    )
+
+    if klass is ExtensionBlock and isinstance(values.dtype, PeriodDtype):
+        # GH-44681 changed PeriodArray to be stored in the 2D
+        # NDArrayBackedExtensionBlock instead of ExtensionBlock
+        # -> still allow ExtensionBlock to be passed in this case for back compat
+        klass = None
+
+    if klass is None:
+        dtype = dtype or values.dtype
+        klass = get_block_type(dtype)
+
+    elif klass is DatetimeTZBlock and not isinstance(values.dtype, DatetimeTZDtype):
+        # pyarrow calls get here
+        values = DatetimeArray._simple_new(
+            # error: Argument "dtype" to "_simple_new" of "DatetimeArray" has
+            # incompatible type "Union[ExtensionDtype, dtype[Any], None]";
+            # expected "Union[dtype[datetime64], DatetimeTZDtype]"
+            values,
+            dtype=dtype,  # type: ignore[arg-type]
+        )
+
+    if not isinstance(placement, BlockPlacement):
+        placement = BlockPlacement(placement)
+
+    ndim = maybe_infer_ndim(values, placement, ndim)
+    if isinstance(values.dtype, (PeriodDtype, DatetimeTZDtype)):
+        # GH#41168 ensure we can pass 1D dt64tz values
+        # More generally, any EA dtype that isn't is_1d_only_ea_dtype
+        values = extract_array(values, extract_numpy=True)
+        values = ensure_block_shape(values, ndim)
+
+    check_ndim(values, placement, ndim)
+    values = maybe_coerce_values(values)
+    return klass(values, ndim=ndim, placement=placement)
+
+
+def maybe_infer_ndim(values, placement: BlockPlacement, ndim: int | None) -> int:
+    """
+    If `ndim` is not provided, infer it from placement and values.
+    """
+    if ndim is None:
+        # GH#38134 Block constructor now assumes ndim is not None
+        if not isinstance(values.dtype, np.dtype):
+            if len(placement) != 1:
+                ndim = 1
+            else:
+                ndim = 2
+        else:
+            ndim = values.ndim
+    return ndim
+
+
+def __getattr__(name: str):
+    # GH#55139
+    import warnings
+
+    if name in [
+        "Block",
+        "ExtensionBlock",
+        "DatetimeTZBlock",
+        "create_block_manager_from_blocks",
+    ]:
+        # GH#33892
+        warnings.warn(
+            f"{name} is deprecated and will be removed in a future version. "
+            "Use public APIs instead.",
+            DeprecationWarning,
+            # https://github.com/pandas-dev/pandas/pull/55139#pullrequestreview-1720690758
+            # on hard-coding stacklevel
+            stacklevel=2,
+        )
+
+        if name == "create_block_manager_from_blocks":
+            from pandas.core.internals.managers import create_block_manager_from_blocks
+
+            return create_block_manager_from_blocks
+
+        elif name == "Block":
+            from pandas.core.internals.blocks import Block
+
+            return Block
+
+        elif name == "DatetimeTZBlock":
+            from pandas.core.internals.blocks import DatetimeTZBlock
+
+            return DatetimeTZBlock
+
+        elif name == "ExtensionBlock":
+            from pandas.core.internals.blocks import ExtensionBlock
+
+            return ExtensionBlock
+
+    raise AttributeError(
+        f"module 'pandas.core.internals.api' has no attribute '{name}'"
+    )

venv/lib/python3.10/site-packages/pandas/core/internals/array_manager.py

@@ -0,0 +1,1340 @@
+"""
+Experimental manager based on storing a collection of 1D arrays
+"""
+from __future__ import annotations
+
+import itertools
+from typing import (
+    TYPE_CHECKING,
+    Callable,
+    Literal,
+)
+
+import numpy as np
+
+from pandas._libs import (
+    NaT,
+    lib,
+)
+
+from pandas.core.dtypes.astype import (
+    astype_array,
+    astype_array_safe,
+)
+from pandas.core.dtypes.cast import (
+    ensure_dtype_can_hold_na,
+    find_common_type,
+    infer_dtype_from_scalar,
+    np_find_common_type,
+)
+from pandas.core.dtypes.common import (
+    ensure_platform_int,
+    is_datetime64_ns_dtype,
+    is_integer,
+    is_numeric_dtype,
+    is_object_dtype,
+    is_timedelta64_ns_dtype,
+)
+from pandas.core.dtypes.dtypes import ExtensionDtype
+from pandas.core.dtypes.generic import (
+    ABCDataFrame,
+    ABCSeries,
+)
+from pandas.core.dtypes.missing import (
+    array_equals,
+    isna,
+    na_value_for_dtype,
+)
+
+import pandas.core.algorithms as algos
+from pandas.core.array_algos.quantile import quantile_compat
+from pandas.core.array_algos.take import take_1d
+from pandas.core.arrays import (
+    DatetimeArray,
+    ExtensionArray,
+    NumpyExtensionArray,
+    TimedeltaArray,
+)
+from pandas.core.construction import (
+    ensure_wrapped_if_datetimelike,
+    extract_array,
+    sanitize_array,
+)
+from pandas.core.indexers import (
+    maybe_convert_indices,
+    validate_indices,
+)
+from pandas.core.indexes.api import (
+    Index,
+    ensure_index,
+)
+from pandas.core.indexes.base import get_values_for_csv
+from pandas.core.internals.base import (
+    DataManager,
+    SingleDataManager,
+    ensure_np_dtype,
+    interleaved_dtype,
+)
+from pandas.core.internals.blocks import (
+    BlockPlacement,
+    ensure_block_shape,
+    external_values,
+    extract_pandas_array,
+    maybe_coerce_values,
+    new_block,
+)
+from pandas.core.internals.managers import make_na_array
+
+if TYPE_CHECKING:
+    from collections.abc import Hashable
+
+    from pandas._typing import (
+        ArrayLike,
+        AxisInt,
+        DtypeObj,
+        QuantileInterpolation,
+        Self,
+        npt,
+    )
+
+
+class BaseArrayManager(DataManager):
+    """
+    Core internal data structure to implement DataFrame and Series.
+
+    Alternative to the BlockManager, storing a list of 1D arrays instead of
+    Blocks.
+
+    This is *not* a public API class
+
+    Parameters
+    ----------
+    arrays : Sequence of arrays
+    axes : Sequence of Index
+    verify_integrity : bool, default True
+
+    """
+
+    __slots__ = [
+        "_axes",  # private attribute, because 'axes' has different order, see below
+        "arrays",
+    ]
+
+    arrays: list[np.ndarray | ExtensionArray]
+    _axes: list[Index]
+
+    def __init__(
+        self,
+        arrays: list[np.ndarray | ExtensionArray],
+        axes: list[Index],
+        verify_integrity: bool = True,
+    ) -> None:
+        raise NotImplementedError
+
+    def make_empty(self, axes=None) -> Self:
+        """Return an empty ArrayManager with the items axis of len 0 (no columns)"""
+        if axes is None:
+            axes = [self.axes[1:], Index([])]
+
+        arrays: list[np.ndarray | ExtensionArray] = []
+        return type(self)(arrays, axes)
+
+    @property
+    def items(self) -> Index:
+        return self._axes[-1]
+
+    @property
+    # error: Signature of "axes" incompatible with supertype "DataManager"
+    def axes(self) -> list[Index]:  # type: ignore[override]
+        # mypy doesn't work to override attribute with property
+        # see https://github.com/python/mypy/issues/4125
+        """Axes is BlockManager-compatible order (columns, rows)"""
+        return [self._axes[1], self._axes[0]]
+
+    @property
+    def shape_proper(self) -> tuple[int, ...]:
+        # this returns (n_rows, n_columns)
+        return tuple(len(ax) for ax in self._axes)
+
+    @staticmethod
+    def _normalize_axis(axis: AxisInt) -> int:
+        # switch axis
+        axis = 1 if axis == 0 else 0
+        return axis
+
+    def set_axis(self, axis: AxisInt, new_labels: Index) -> None:
+        # Caller is responsible for ensuring we have an Index object.
+        self._validate_set_axis(axis, new_labels)
+        axis = self._normalize_axis(axis)
+        self._axes[axis] = new_labels
+
+    def get_dtypes(self) -> npt.NDArray[np.object_]:
+        return np.array([arr.dtype for arr in self.arrays], dtype="object")
+
+    def add_references(self, mgr: BaseArrayManager) -> None:
+        """
+        Only implemented on the BlockManager level
+        """
+        return
+
+    def __getstate__(self):
+        return self.arrays, self._axes
+
+    def __setstate__(self, state) -> None:
+        self.arrays = state[0]
+        self._axes = state[1]
+
+    def __repr__(self) -> str:
+        output = type(self).__name__
+        output += f"\nIndex: {self._axes[0]}"
+        if self.ndim == 2:
+            output += f"\nColumns: {self._axes[1]}"
+        output += f"\n{len(self.arrays)} arrays:"
+        for arr in self.arrays:
+            output += f"\n{arr.dtype}"
+        return output
+
+    def apply(
+        self,
+        f,
+        align_keys: list[str] | None = None,
+        **kwargs,
+    ) -> Self:
+        """
+        Iterate over the arrays, collect and create a new ArrayManager.
+
+        Parameters
+        ----------
+        f : str or callable
+            Name of the Array method to apply.
+        align_keys: List[str] or None, default None
+        **kwargs
+            Keywords to pass to `f`
+
+        Returns
+        -------
+        ArrayManager
+        """
+        assert "filter" not in kwargs
+
+        align_keys = align_keys or []
+        result_arrays: list[ArrayLike] = []
+        # fillna: Series/DataFrame is responsible for making sure value is aligned
+
+        aligned_args = {k: kwargs[k] for k in align_keys}
+
+        if f == "apply":
+            f = kwargs.pop("func")
+
+        for i, arr in enumerate(self.arrays):
+            if aligned_args:
+                for k, obj in aligned_args.items():
+                    if isinstance(obj, (ABCSeries, ABCDataFrame)):
+                        # The caller is responsible for ensuring that
+                        #  obj.axes[-1].equals(self.items)
+                        if obj.ndim == 1:
+                            kwargs[k] = obj.iloc[i]
+                        else:
+                            kwargs[k] = obj.iloc[:, i]._values
+                    else:
+                        # otherwise we have an array-like
+                        kwargs[k] = obj[i]
+
+            if callable(f):
+                applied = f(arr, **kwargs)
+            else:
+                applied = getattr(arr, f)(**kwargs)
+
+            result_arrays.append(applied)
+
+        new_axes = self._axes
+        return type(self)(result_arrays, new_axes)
+
+    def apply_with_block(self, f, align_keys=None, **kwargs) -> Self:
+        # switch axis to follow BlockManager logic
+        swap_axis = True
+        if f == "interpolate":
+            swap_axis = False
+        if swap_axis and "axis" in kwargs and self.ndim == 2:
+            kwargs["axis"] = 1 if kwargs["axis"] == 0 else 0
+
+        align_keys = align_keys or []
+        aligned_args = {k: kwargs[k] for k in align_keys}
+
+        result_arrays = []
+
+        for i, arr in enumerate(self.arrays):
+            if aligned_args:
+                for k, obj in aligned_args.items():
+                    if isinstance(obj, (ABCSeries, ABCDataFrame)):
+                        # The caller is responsible for ensuring that
+                        #  obj.axes[-1].equals(self.items)
+                        if obj.ndim == 1:
+                            if self.ndim == 2:
+                                kwargs[k] = obj.iloc[slice(i, i + 1)]._values
+                            else:
+                                kwargs[k] = obj.iloc[:]._values
+                        else:
+                            kwargs[k] = obj.iloc[:, [i]]._values
+                    else:
+                        # otherwise we have an ndarray
+                        if obj.ndim == 2:
+                            kwargs[k] = obj[[i]]
+
+            if isinstance(arr.dtype, np.dtype) and not isinstance(arr, np.ndarray):
+                # i.e. TimedeltaArray, DatetimeArray with tz=None. Need to
+                #  convert for the Block constructors.
+                arr = np.asarray(arr)
+
+            arr = maybe_coerce_values(arr)
+            if self.ndim == 2:
+                arr = ensure_block_shape(arr, 2)
+                bp = BlockPlacement(slice(0, 1, 1))
+                block = new_block(arr, placement=bp, ndim=2)
+            else:
+                bp = BlockPlacement(slice(0, len(self), 1))
+                block = new_block(arr, placement=bp, ndim=1)
+
+            applied = getattr(block, f)(**kwargs)
+            if isinstance(applied, list):
+                applied = applied[0]
+            arr = applied.values
+            if self.ndim == 2 and arr.ndim == 2:
+                # 2D for np.ndarray or DatetimeArray/TimedeltaArray
+                assert len(arr) == 1
+                # error: No overload variant of "__getitem__" of "ExtensionArray"
+                # matches argument type "Tuple[int, slice]"
+                arr = arr[0, :]  # type: ignore[call-overload]
+            result_arrays.append(arr)
+
+        return type(self)(result_arrays, self._axes)
+
+    def setitem(self, indexer, value, warn: bool = True) -> Self:
+        return self.apply_with_block("setitem", indexer=indexer, value=value)
+
+    def diff(self, n: int) -> Self:
+        assert self.ndim == 2  # caller ensures
+        return self.apply(algos.diff, n=n)
+
+    def astype(self, dtype, copy: bool | None = False, errors: str = "raise") -> Self:
+        if copy is None:
+            copy = True
+
+        return self.apply(astype_array_safe, dtype=dtype, copy=copy, errors=errors)
+
+    def convert(self, copy: bool | None) -> Self:
+        if copy is None:
+            copy = True
+
+        def _convert(arr):
+            if is_object_dtype(arr.dtype):
+                # extract NumpyExtensionArray for tests that patch
+                #  NumpyExtensionArray._typ
+                arr = np.asarray(arr)
+                result = lib.maybe_convert_objects(
+                    arr,
+                    convert_non_numeric=True,
+                )
+                if result is arr and copy:
+                    return arr.copy()
+                return result
+            else:
+                return arr.copy() if copy else arr
+
+        return self.apply(_convert)
+
+    def get_values_for_csv(
+        self, *, float_format, date_format, decimal, na_rep: str = "nan", quoting=None
+    ) -> Self:
+        return self.apply(
+            get_values_for_csv,
+            na_rep=na_rep,
+            quoting=quoting,
+            float_format=float_format,
+            date_format=date_format,
+            decimal=decimal,
+        )
+
+    @property
+    def any_extension_types(self) -> bool:
+        """Whether any of the blocks in this manager are extension blocks"""
+        return False  # any(block.is_extension for block in self.blocks)
+
+    @property
+    def is_view(self) -> bool:
+        """return a boolean if we are a single block and are a view"""
+        # TODO what is this used for?
+        return False
+
+    @property
+    def is_single_block(self) -> bool:
+        return len(self.arrays) == 1
+
+    def _get_data_subset(self, predicate: Callable) -> Self:
+        indices = [i for i, arr in enumerate(self.arrays) if predicate(arr)]
+        arrays = [self.arrays[i] for i in indices]
+        # TODO copy?
+        # Note: using Index.take ensures we can retain e.g. DatetimeIndex.freq,
+        #  see test_describe_datetime_columns
+        taker = np.array(indices, dtype="intp")
+        new_cols = self._axes[1].take(taker)
+        new_axes = [self._axes[0], new_cols]
+        return type(self)(arrays, new_axes, verify_integrity=False)
+
+    def get_bool_data(self, copy: bool = False) -> Self:
+        """
+        Select columns that are bool-dtype and object-dtype columns that are all-bool.
+
+        Parameters
+        ----------
+        copy : bool, default False
+            Whether to copy the blocks
+        """
+        return self._get_data_subset(lambda x: x.dtype == np.dtype(bool))
+
+    def get_numeric_data(self, copy: bool = False) -> Self:
+        """
+        Select columns that have a numeric dtype.
+
+        Parameters
+        ----------
+        copy : bool, default False
+            Whether to copy the blocks
+        """
+        return self._get_data_subset(
+            lambda arr: is_numeric_dtype(arr.dtype)
+            or getattr(arr.dtype, "_is_numeric", False)
+        )
+
+    def copy(self, deep: bool | Literal["all"] | None = True) -> Self:
+        """
+        Make deep or shallow copy of ArrayManager
+
+        Parameters
+        ----------
+        deep : bool or string, default True
+            If False, return shallow copy (do not copy data)
+            If 'all', copy data and a deep copy of the index
+
+        Returns
+        -------
+        BlockManager
+        """
+        if deep is None:
+            # ArrayManager does not yet support CoW, so deep=None always means
+            # deep=True for now
+            deep = True
+
+        # this preserves the notion of view copying of axes
+        if deep:
+            # hit in e.g. tests.io.json.test_pandas
+
+            def copy_func(ax):
+                return ax.copy(deep=True) if deep == "all" else ax.view()
+
+            new_axes = [copy_func(ax) for ax in self._axes]
+        else:
+            new_axes = list(self._axes)
+
+        if deep:
+            new_arrays = [arr.copy() for arr in self.arrays]
+        else:
+            new_arrays = list(self.arrays)
+        return type(self)(new_arrays, new_axes, verify_integrity=False)
+
+    def reindex_indexer(
+        self,
+        new_axis,
+        indexer,
+        axis: AxisInt,
+        fill_value=None,
+        allow_dups: bool = False,
+        copy: bool | None = True,
+        # ignored keywords
+        only_slice: bool = False,
+        # ArrayManager specific keywords
+        use_na_proxy: bool = False,
+    ) -> Self:
+        axis = self._normalize_axis(axis)
+        return self._reindex_indexer(
+            new_axis,
+            indexer,
+            axis,
+            fill_value,
+            allow_dups,
+            copy,
+            use_na_proxy,
+        )
+
+    def _reindex_indexer(
+        self,
+        new_axis,
+        indexer: npt.NDArray[np.intp] | None,
+        axis: AxisInt,
+        fill_value=None,
+        allow_dups: bool = False,
+        copy: bool | None = True,
+        use_na_proxy: bool = False,
+    ) -> Self:
+        """
+        Parameters
+        ----------
+        new_axis : Index
+        indexer : ndarray[intp] or None
+        axis : int
+        fill_value : object, default None
+        allow_dups : bool, default False
+        copy : bool, default True
+
+
+        pandas-indexer with -1's only.
+        """
+        if copy is None:
+            # ArrayManager does not yet support CoW, so deep=None always means
+            # deep=True for now
+            copy = True
+
+        if indexer is None:
+            if new_axis is self._axes[axis] and not copy:
+                return self
+
+            result = self.copy(deep=copy)
+            result._axes = list(self._axes)
+            result._axes[axis] = new_axis
+            return result
+
+        # some axes don't allow reindexing with dups
+        if not allow_dups:
+            self._axes[axis]._validate_can_reindex(indexer)
+
+        if axis >= self.ndim:
+            raise IndexError("Requested axis not found in manager")
+
+        if axis == 1:
+            new_arrays = []
+            for i in indexer:
+                if i == -1:
+                    arr = self._make_na_array(
+                        fill_value=fill_value, use_na_proxy=use_na_proxy
+                    )
+                else:
+                    arr = self.arrays[i]
+                    if copy:
+                        arr = arr.copy()
+                new_arrays.append(arr)
+
+        else:
+            validate_indices(indexer, len(self._axes[0]))
+            indexer = ensure_platform_int(indexer)
+            mask = indexer == -1
+            needs_masking = mask.any()
+            new_arrays = [
+                take_1d(
+                    arr,
+                    indexer,
+                    allow_fill=needs_masking,
+                    fill_value=fill_value,
+                    mask=mask,
+                    # if fill_value is not None else blk.fill_value
+                )
+                for arr in self.arrays
+            ]
+
+        new_axes = list(self._axes)
+        new_axes[axis] = new_axis
+
+        return type(self)(new_arrays, new_axes, verify_integrity=False)
+
+    def take(
+        self,
+        indexer: npt.NDArray[np.intp],
+        axis: AxisInt = 1,
+        verify: bool = True,
+    ) -> Self:
+        """
+        Take items along any axis.
+        """
+        assert isinstance(indexer, np.ndarray), type(indexer)
+        assert indexer.dtype == np.intp, indexer.dtype
+
+        axis = self._normalize_axis(axis)
+
+        if not indexer.ndim == 1:
+            raise ValueError("indexer should be 1-dimensional")
+
+        n = self.shape_proper[axis]
+        indexer = maybe_convert_indices(indexer, n, verify=verify)
+
+        new_labels = self._axes[axis].take(indexer)
+        return self._reindex_indexer(
+            new_axis=new_labels, indexer=indexer, axis=axis, allow_dups=True
+        )
+
+    def _make_na_array(self, fill_value=None, use_na_proxy: bool = False):
+        if use_na_proxy:
+            assert fill_value is None
+            return NullArrayProxy(self.shape_proper[0])
+
+        if fill_value is None:
+            fill_value = np.nan
+
+        dtype, fill_value = infer_dtype_from_scalar(fill_value)
+        array_values = make_na_array(dtype, self.shape_proper[:1], fill_value)
+        return array_values
+
+    def _equal_values(self, other) -> bool:
+        """
+        Used in .equals defined in base class. Only check the column values
+        assuming shape and indexes have already been checked.
+        """
+        for left, right in zip(self.arrays, other.arrays):
+            if not array_equals(left, right):
+                return False
+        return True
+
+    # TODO
+    # to_dict
+
+
+class ArrayManager(BaseArrayManager):
+    @property
+    def ndim(self) -> Literal[2]:
+        return 2
+
+    def __init__(
+        self,
+        arrays: list[np.ndarray | ExtensionArray],
+        axes: list[Index],
+        verify_integrity: bool = True,
+    ) -> None:
+        # Note: we are storing the axes in "_axes" in the (row, columns) order
+        # which contrasts the order how it is stored in BlockManager
+        self._axes = axes
+        self.arrays = arrays
+
+        if verify_integrity:
+            self._axes = [ensure_index(ax) for ax in axes]
+            arrays = [extract_pandas_array(x, None, 1)[0] for x in arrays]
+            self.arrays = [maybe_coerce_values(arr) for arr in arrays]
+            self._verify_integrity()
+
+    def _verify_integrity(self) -> None:
+        n_rows, n_columns = self.shape_proper
+        if not len(self.arrays) == n_columns:
+            raise ValueError(
+                "Number of passed arrays must equal the size of the column Index: "
+                f"{len(self.arrays)} arrays vs {n_columns} columns."
+            )
+        for arr in self.arrays:
+            if not len(arr) == n_rows:
+                raise ValueError(
+                    "Passed arrays should have the same length as the rows Index: "
+                    f"{len(arr)} vs {n_rows} rows"
+                )
+            if not isinstance(arr, (np.ndarray, ExtensionArray)):
+                raise ValueError(
+                    "Passed arrays should be np.ndarray or ExtensionArray instances, "
+                    f"got {type(arr)} instead"
+                )
+            if not arr.ndim == 1:
+                raise ValueError(
+                    "Passed arrays should be 1-dimensional, got array with "
+                    f"{arr.ndim} dimensions instead."
+                )
+
+    # --------------------------------------------------------------------
+    # Indexing
+
+    def fast_xs(self, loc: int) -> SingleArrayManager:
+        """
+        Return the array corresponding to `frame.iloc[loc]`.
+
+        Parameters
+        ----------
+        loc : int
+
+        Returns
+        -------
+        np.ndarray or ExtensionArray
+        """
+        dtype = interleaved_dtype([arr.dtype for arr in self.arrays])
+
+        values = [arr[loc] for arr in self.arrays]
+        if isinstance(dtype, ExtensionDtype):
+            result = dtype.construct_array_type()._from_sequence(values, dtype=dtype)
+        # for datetime64/timedelta64, the np.ndarray constructor cannot handle pd.NaT
+        elif is_datetime64_ns_dtype(dtype):
+            result = DatetimeArray._from_sequence(values, dtype=dtype)._ndarray
+        elif is_timedelta64_ns_dtype(dtype):
+            result = TimedeltaArray._from_sequence(values, dtype=dtype)._ndarray
+        else:
+            result = np.array(values, dtype=dtype)
+        return SingleArrayManager([result], [self._axes[1]])
+
+    def get_slice(self, slobj: slice, axis: AxisInt = 0) -> ArrayManager:
+        axis = self._normalize_axis(axis)
+
+        if axis == 0:
+            arrays = [arr[slobj] for arr in self.arrays]
+        elif axis == 1:
+            arrays = self.arrays[slobj]
+
+        new_axes = list(self._axes)
+        new_axes[axis] = new_axes[axis]._getitem_slice(slobj)
+
+        return type(self)(arrays, new_axes, verify_integrity=False)
+
+    def iget(self, i: int) -> SingleArrayManager:
+        """
+        Return the data as a SingleArrayManager.
+        """
+        values = self.arrays[i]
+        return SingleArrayManager([values], [self._axes[0]])
+
+    def iget_values(self, i: int) -> ArrayLike:
+        """
+        Return the data for column i as the values (ndarray or ExtensionArray).
+        """
+        return self.arrays[i]
+
+    @property
+    def column_arrays(self) -> list[ArrayLike]:
+        """
+        Used in the JSON C code to access column arrays.
+        """
+
+        return [np.asarray(arr) for arr in self.arrays]
+
+    def iset(
+        self,
+        loc: int | slice | np.ndarray,
+        value: ArrayLike,
+        inplace: bool = False,
+        refs=None,
+    ) -> None:
+        """
+        Set new column(s).
+
+        This changes the ArrayManager in-place, but replaces (an) existing
+        column(s), not changing column values in-place).
+
+        Parameters
+        ----------
+        loc : integer, slice or boolean mask
+            Positional location (already bounds checked)
+        value : np.ndarray or ExtensionArray
+        inplace : bool, default False
+            Whether overwrite existing array as opposed to replacing it.
+        """
+        # single column -> single integer index
+        if lib.is_integer(loc):
+            # TODO can we avoid needing to unpack this here? That means converting
+            # DataFrame into 1D array when loc is an integer
+            if isinstance(value, np.ndarray) and value.ndim == 2:
+                assert value.shape[1] == 1
+                value = value[:, 0]
+
+            # TODO we receive a datetime/timedelta64 ndarray from DataFrame._iset_item
+            # but we should avoid that and pass directly the proper array
+            value = maybe_coerce_values(value)
+
+            assert isinstance(value, (np.ndarray, ExtensionArray))
+            assert value.ndim == 1
+            assert len(value) == len(self._axes[0])
+            self.arrays[loc] = value
+            return
+
+        # multiple columns -> convert slice or array to integer indices
+        elif isinstance(loc, slice):
+            indices: range | np.ndarray = range(
+                loc.start if loc.start is not None else 0,
+                loc.stop if loc.stop is not None else self.shape_proper[1],
+                loc.step if loc.step is not None else 1,
+            )
+        else:
+            assert isinstance(loc, np.ndarray)
+            assert loc.dtype == "bool"
+            indices = np.nonzero(loc)[0]
+
+        assert value.ndim == 2
+        assert value.shape[0] == len(self._axes[0])
+
+        for value_idx, mgr_idx in enumerate(indices):
+            # error: No overload variant of "__getitem__" of "ExtensionArray" matches
+            # argument type "Tuple[slice, int]"
+            value_arr = value[:, value_idx]  # type: ignore[call-overload]
+            self.arrays[mgr_idx] = value_arr
+        return
+
+    def column_setitem(
+        self, loc: int, idx: int | slice | np.ndarray, value, inplace_only: bool = False
+    ) -> None:
+        """
+        Set values ("setitem") into a single column (not setting the full column).
+
+        This is a method on the ArrayManager level, to avoid creating an
+        intermediate Series at the DataFrame level (`s = df[loc]; s[idx] = value`)
+        """
+        if not is_integer(loc):
+            raise TypeError("The column index should be an integer")
+        arr = self.arrays[loc]
+        mgr = SingleArrayManager([arr], [self._axes[0]])
+        if inplace_only:
+            mgr.setitem_inplace(idx, value)
+        else:
+            new_mgr = mgr.setitem((idx,), value)
+            # update existing ArrayManager in-place
+            self.arrays[loc] = new_mgr.arrays[0]
+
+    def insert(self, loc: int, item: Hashable, value: ArrayLike, refs=None) -> None:
+        """
+        Insert item at selected position.
+
+        Parameters
+        ----------
+        loc : int
+        item : hashable
+        value : np.ndarray or ExtensionArray
+        """
+        # insert to the axis; this could possibly raise a TypeError
+        new_axis = self.items.insert(loc, item)
+
+        value = extract_array(value, extract_numpy=True)
+        if value.ndim == 2:
+            if value.shape[0] == 1:
+                # error: No overload variant of "__getitem__" of "ExtensionArray"
+                # matches argument type "Tuple[int, slice]"
+                value = value[0, :]  # type: ignore[call-overload]
+            else:
+                raise ValueError(
+                    f"Expected a 1D array, got an array with shape {value.shape}"
+                )
+        value = maybe_coerce_values(value)
+
+        # TODO self.arrays can be empty
+        # assert len(value) == len(self.arrays[0])
+
+        # TODO is this copy needed?
+        arrays = self.arrays.copy()
+        arrays.insert(loc, value)
+
+        self.arrays = arrays
+        self._axes[1] = new_axis
+
+    def idelete(self, indexer) -> ArrayManager:
+        """
+        Delete selected locations in-place (new block and array, same BlockManager)
+        """
+        to_keep = np.ones(self.shape[0], dtype=np.bool_)
+        to_keep[indexer] = False
+
+        self.arrays = [self.arrays[i] for i in np.nonzero(to_keep)[0]]
+        self._axes = [self._axes[0], self._axes[1][to_keep]]
+        return self
+
+    # --------------------------------------------------------------------
+    # Array-wise Operation
+
+    def grouped_reduce(self, func: Callable) -> Self:
+        """
+        Apply grouped reduction function columnwise, returning a new ArrayManager.
+
+        Parameters
+        ----------
+        func : grouped reduction function
+
+        Returns
+        -------
+        ArrayManager
+        """
+        result_arrays: list[np.ndarray] = []
+        result_indices: list[int] = []
+
+        for i, arr in enumerate(self.arrays):
+            # grouped_reduce functions all expect 2D arrays
+            arr = ensure_block_shape(arr, ndim=2)
+            res = func(arr)
+            if res.ndim == 2:
+                # reverse of ensure_block_shape
+                assert res.shape[0] == 1
+                res = res[0]
+
+            result_arrays.append(res)
+            result_indices.append(i)
+
+        if len(result_arrays) == 0:
+            nrows = 0
+        else:
+            nrows = result_arrays[0].shape[0]
+        index = Index(range(nrows))
+
+        columns = self.items
+
+        # error: Argument 1 to "ArrayManager" has incompatible type "List[ndarray]";
+        # expected "List[Union[ndarray, ExtensionArray]]"
+        return type(self)(result_arrays, [index, columns])  # type: ignore[arg-type]
+
+    def reduce(self, func: Callable) -> Self:
+        """
+        Apply reduction function column-wise, returning a single-row ArrayManager.
+
+        Parameters
+        ----------
+        func : reduction function
+
+        Returns
+        -------
+        ArrayManager
+        """
+        result_arrays: list[np.ndarray] = []
+        for i, arr in enumerate(self.arrays):
+            res = func(arr, axis=0)
+
+            # TODO NaT doesn't preserve dtype, so we need to ensure to create
+            # a timedelta result array if original was timedelta
+            # what if datetime results in timedelta? (eg std)
+            dtype = arr.dtype if res is NaT else None
+            result_arrays.append(
+                sanitize_array([res], None, dtype=dtype)  # type: ignore[arg-type]
+            )
+
+        index = Index._simple_new(np.array([None], dtype=object))  # placeholder
+        columns = self.items
+
+        # error: Argument 1 to "ArrayManager" has incompatible type "List[ndarray]";
+        # expected "List[Union[ndarray, ExtensionArray]]"
+        new_mgr = type(self)(result_arrays, [index, columns])  # type: ignore[arg-type]
+        return new_mgr
+
+    def operate_blockwise(self, other: ArrayManager, array_op) -> ArrayManager:
+        """
+        Apply array_op blockwise with another (aligned) BlockManager.
+        """
+        # TODO what if `other` is BlockManager ?
+        left_arrays = self.arrays
+        right_arrays = other.arrays
+        result_arrays = [
+            array_op(left, right) for left, right in zip(left_arrays, right_arrays)
+        ]
+        return type(self)(result_arrays, self._axes)
+
+    def quantile(
+        self,
+        *,
+        qs: Index,  # with dtype float64
+        transposed: bool = False,
+        interpolation: QuantileInterpolation = "linear",
+    ) -> ArrayManager:
+        arrs = [ensure_block_shape(x, 2) for x in self.arrays]
+        new_arrs = [
+            quantile_compat(x, np.asarray(qs._values), interpolation) for x in arrs
+        ]
+        for i, arr in enumerate(new_arrs):
+            if arr.ndim == 2:
+                assert arr.shape[0] == 1, arr.shape
+                new_arrs[i] = arr[0]
+
+        axes = [qs, self._axes[1]]
+        return type(self)(new_arrs, axes)
+
+    # ----------------------------------------------------------------
+
+    def unstack(self, unstacker, fill_value) -> ArrayManager:
+        """
+        Return a BlockManager with all blocks unstacked.
+
+        Parameters
+        ----------
+        unstacker : reshape._Unstacker
+        fill_value : Any
+            fill_value for newly introduced missing values.
+
+        Returns
+        -------
+        unstacked : BlockManager
+        """
+        indexer, _ = unstacker._indexer_and_to_sort
+        if unstacker.mask.all():
+            new_indexer = indexer
+            allow_fill = False
+            new_mask2D = None
+            needs_masking = None
+        else:
+            new_indexer = np.full(unstacker.mask.shape, -1)
+            new_indexer[unstacker.mask] = indexer
+            allow_fill = True
+            # calculating the full mask once and passing it to take_1d is faster
+            # than letting take_1d calculate it in each repeated call
+            new_mask2D = (~unstacker.mask).reshape(*unstacker.full_shape)
+            needs_masking = new_mask2D.any(axis=0)
+        new_indexer2D = new_indexer.reshape(*unstacker.full_shape)
+        new_indexer2D = ensure_platform_int(new_indexer2D)
+
+        new_arrays = []
+        for arr in self.arrays:
+            for i in range(unstacker.full_shape[1]):
+                if allow_fill:
+                    # error: Value of type "Optional[Any]" is not indexable  [index]
+                    new_arr = take_1d(
+                        arr,
+                        new_indexer2D[:, i],
+                        allow_fill=needs_masking[i],  # type: ignore[index]
+                        fill_value=fill_value,
+                        mask=new_mask2D[:, i],  # type: ignore[index]
+                    )
+                else:
+                    new_arr = take_1d(arr, new_indexer2D[:, i], allow_fill=False)
+                new_arrays.append(new_arr)
+
+        new_index = unstacker.new_index
+        new_columns = unstacker.get_new_columns(self._axes[1])
+        new_axes = [new_index, new_columns]
+
+        return type(self)(new_arrays, new_axes, verify_integrity=False)
+
+    def as_array(
+        self,
+        dtype=None,
+        copy: bool = False,
+        na_value: object = lib.no_default,
+    ) -> np.ndarray:
+        """
+        Convert the blockmanager data into an numpy array.
+
+        Parameters
+        ----------
+        dtype : object, default None
+            Data type of the return array.
+        copy : bool, default False
+            If True then guarantee that a copy is returned. A value of
+            False does not guarantee that the underlying data is not
+            copied.
+        na_value : object, default lib.no_default
+            Value to be used as the missing value sentinel.
+
+        Returns
+        -------
+        arr : ndarray
+        """
+        if len(self.arrays) == 0:
+            empty_arr = np.empty(self.shape, dtype=float)
+            return empty_arr.transpose()
+
+        # We want to copy when na_value is provided to avoid
+        # mutating the original object
+        copy = copy or na_value is not lib.no_default
+
+        if not dtype:
+            dtype = interleaved_dtype([arr.dtype for arr in self.arrays])
+
+        dtype = ensure_np_dtype(dtype)
+
+        result = np.empty(self.shape_proper, dtype=dtype)
+
+        for i, arr in enumerate(self.arrays):
+            arr = arr.astype(dtype, copy=copy)
+            result[:, i] = arr
+
+        if na_value is not lib.no_default:
+            result[isna(result)] = na_value
+
+        return result
+
+    @classmethod
+    def concat_horizontal(cls, mgrs: list[Self], axes: list[Index]) -> Self:
+        """
+        Concatenate uniformly-indexed ArrayManagers horizontally.
+        """
+        # concatting along the columns -> combine reindexed arrays in a single manager
+        arrays = list(itertools.chain.from_iterable([mgr.arrays for mgr in mgrs]))
+        new_mgr = cls(arrays, [axes[1], axes[0]], verify_integrity=False)
+        return new_mgr
+
+    @classmethod
+    def concat_vertical(cls, mgrs: list[Self], axes: list[Index]) -> Self:
+        """
+        Concatenate uniformly-indexed ArrayManagers vertically.
+        """
+        # concatting along the rows -> concat the reindexed arrays
+        # TODO(ArrayManager) doesn't yet preserve the correct dtype
+        arrays = [
+            concat_arrays([mgrs[i].arrays[j] for i in range(len(mgrs))])
+            for j in range(len(mgrs[0].arrays))
+        ]
+        new_mgr = cls(arrays, [axes[1], axes[0]], verify_integrity=False)
+        return new_mgr
+
+
+class SingleArrayManager(BaseArrayManager, SingleDataManager):
+    __slots__ = [
+        "_axes",  # private attribute, because 'axes' has different order, see below
+        "arrays",
+    ]
+
+    arrays: list[np.ndarray | ExtensionArray]
+    _axes: list[Index]
+
+    @property
+    def ndim(self) -> Literal[1]:
+        return 1
+
+    def __init__(
+        self,
+        arrays: list[np.ndarray | ExtensionArray],
+        axes: list[Index],
+        verify_integrity: bool = True,
+    ) -> None:
+        self._axes = axes
+        self.arrays = arrays
+
+        if verify_integrity:
+            assert len(axes) == 1
+            assert len(arrays) == 1
+            self._axes = [ensure_index(ax) for ax in self._axes]
+            arr = arrays[0]
+            arr = maybe_coerce_values(arr)
+            arr = extract_pandas_array(arr, None, 1)[0]
+            self.arrays = [arr]
+            self._verify_integrity()
+
+    def _verify_integrity(self) -> None:
+        (n_rows,) = self.shape
+        assert len(self.arrays) == 1
+        arr = self.arrays[0]
+        assert len(arr) == n_rows
+        if not arr.ndim == 1:
+            raise ValueError(
+                "Passed array should be 1-dimensional, got array with "
+                f"{arr.ndim} dimensions instead."
+            )
+
+    @staticmethod
+    def _normalize_axis(axis):
+        return axis
+
+    def make_empty(self, axes=None) -> Self:
+        """Return an empty ArrayManager with index/array of length 0"""
+        if axes is None:
+            axes = [Index([], dtype=object)]
+        array: np.ndarray = np.array([], dtype=self.dtype)
+        return type(self)([array], axes)
+
+    @classmethod
+    def from_array(cls, array, index) -> SingleArrayManager:
+        return cls([array], [index])
+
+    # error: Cannot override writeable attribute with read-only property
+    @property
+    def axes(self) -> list[Index]:  # type: ignore[override]
+        return self._axes
+
+    @property
+    def index(self) -> Index:
+        return self._axes[0]
+
+    @property
+    def dtype(self):
+        return self.array.dtype
+
+    def external_values(self):
+        """The array that Series.values returns"""
+        return external_values(self.array)
+
+    def internal_values(self):
+        """The array that Series._values returns"""
+        return self.array
+
+    def array_values(self):
+        """The array that Series.array returns"""
+        arr = self.array
+        if isinstance(arr, np.ndarray):
+            arr = NumpyExtensionArray(arr)
+        return arr
+
+    @property
+    def _can_hold_na(self) -> bool:
+        if isinstance(self.array, np.ndarray):
+            return self.array.dtype.kind not in "iub"
+        else:
+            # ExtensionArray
+            return self.array._can_hold_na
+
+    @property
+    def is_single_block(self) -> bool:
+        return True
+
+    def fast_xs(self, loc: int) -> SingleArrayManager:
+        raise NotImplementedError("Use series._values[loc] instead")
+
+    def get_slice(self, slobj: slice, axis: AxisInt = 0) -> SingleArrayManager:
+        if axis >= self.ndim:
+            raise IndexError("Requested axis not found in manager")
+
+        new_array = self.array[slobj]
+        new_index = self.index._getitem_slice(slobj)
+        return type(self)([new_array], [new_index], verify_integrity=False)
+
+    def get_rows_with_mask(self, indexer: npt.NDArray[np.bool_]) -> SingleArrayManager:
+        new_array = self.array[indexer]
+        new_index = self.index[indexer]
+        return type(self)([new_array], [new_index])
+
+    # error: Signature of "apply" incompatible with supertype "BaseArrayManager"
+    def apply(self, func, **kwargs) -> Self:  # type: ignore[override]
+        if callable(func):
+            new_array = func(self.array, **kwargs)
+        else:
+            new_array = getattr(self.array, func)(**kwargs)
+        return type(self)([new_array], self._axes)
+
+    def setitem(self, indexer, value, warn: bool = True) -> SingleArrayManager:
+        """
+        Set values with indexer.
+
+        For SingleArrayManager, this backs s[indexer] = value
+
+        See `setitem_inplace` for a version that works inplace and doesn't
+        return a new Manager.
+        """
+        if isinstance(indexer, np.ndarray) and indexer.ndim > self.ndim:
+            raise ValueError(f"Cannot set values with ndim > {self.ndim}")
+        return self.apply_with_block("setitem", indexer=indexer, value=value)
+
+    def idelete(self, indexer) -> SingleArrayManager:
+        """
+        Delete selected locations in-place (new array, same ArrayManager)
+        """
+        to_keep = np.ones(self.shape[0], dtype=np.bool_)
+        to_keep[indexer] = False
+
+        self.arrays = [self.arrays[0][to_keep]]
+        self._axes = [self._axes[0][to_keep]]
+        return self
+
+    def _get_data_subset(self, predicate: Callable) -> SingleArrayManager:
+        # used in get_numeric_data / get_bool_data
+        if predicate(self.array):
+            return type(self)(self.arrays, self._axes, verify_integrity=False)
+        else:
+            return self.make_empty()
+
+    def set_values(self, values: ArrayLike) -> None:
+        """
+        Set (replace) the values of the SingleArrayManager in place.
+
+        Use at your own risk! This does not check if the passed values are
+        valid for the current SingleArrayManager (length, dtype, etc).
+        """
+        self.arrays[0] = values
+
+    def to_2d_mgr(self, columns: Index) -> ArrayManager:
+        """
+        Manager analogue of Series.to_frame
+        """
+        arrays = [self.arrays[0]]
+        axes = [self.axes[0], columns]
+
+        return ArrayManager(arrays, axes, verify_integrity=False)
+
+
+class NullArrayProxy:
+    """
+    Proxy object for an all-NA array.
+
+    Only stores the length of the array, and not the dtype. The dtype
+    will only be known when actually concatenating (after determining the
+    common dtype, for which this proxy is ignored).
+    Using this object avoids that the internals/concat.py needs to determine
+    the proper dtype and array type.
+    """
+
+    ndim = 1
+
+    def __init__(self, n: int) -> None:
+        self.n = n
+
+    @property
+    def shape(self) -> tuple[int]:
+        return (self.n,)
+
+    def to_array(self, dtype: DtypeObj) -> ArrayLike:
+        """
+        Helper function to create the actual all-NA array from the NullArrayProxy
+        object.
+
+        Parameters
+        ----------
+        arr : NullArrayProxy
+        dtype : the dtype for the resulting array
+
+        Returns
+        -------
+        np.ndarray or ExtensionArray
+        """
+        if isinstance(dtype, ExtensionDtype):
+            empty = dtype.construct_array_type()._from_sequence([], dtype=dtype)
+            indexer = -np.ones(self.n, dtype=np.intp)
+            return empty.take(indexer, allow_fill=True)
+        else:
+            # when introducing missing values, int becomes float, bool becomes object
+            dtype = ensure_dtype_can_hold_na(dtype)
+            fill_value = na_value_for_dtype(dtype)
+            arr = np.empty(self.n, dtype=dtype)
+            arr.fill(fill_value)
+            return ensure_wrapped_if_datetimelike(arr)
+
+
+def concat_arrays(to_concat: list) -> ArrayLike:
+    """
+    Alternative for concat_compat but specialized for use in the ArrayManager.
+
+    Differences: only deals with 1D arrays (no axis keyword), assumes
+    ensure_wrapped_if_datetimelike and does not skip empty arrays to determine
+    the dtype.
+    In addition ensures that all NullArrayProxies get replaced with actual
+    arrays.
+
+    Parameters
+    ----------
+    to_concat : list of arrays
+
+    Returns
+    -------
+    np.ndarray or ExtensionArray
+    """
+    # ignore the all-NA proxies to determine the resulting dtype
+    to_concat_no_proxy = [x for x in to_concat if not isinstance(x, NullArrayProxy)]
+
+    dtypes = {x.dtype for x in to_concat_no_proxy}
+    single_dtype = len(dtypes) == 1
+
+    if single_dtype:
+        target_dtype = to_concat_no_proxy[0].dtype
+    elif all(lib.is_np_dtype(x, "iub") for x in dtypes):
+        # GH#42092
+        target_dtype = np_find_common_type(*dtypes)
+    else:
+        target_dtype = find_common_type([arr.dtype for arr in to_concat_no_proxy])
+
+    to_concat = [
+        arr.to_array(target_dtype)
+        if isinstance(arr, NullArrayProxy)
+        else astype_array(arr, target_dtype, copy=False)
+        for arr in to_concat
+    ]
+
+    if isinstance(to_concat[0], ExtensionArray):
+        cls = type(to_concat[0])
+        return cls._concat_same_type(to_concat)
+
+    result = np.concatenate(to_concat)
+
+    # TODO decide on exact behaviour (we shouldn't do this only for empty result)
+    # see https://github.com/pandas-dev/pandas/issues/39817
+    if len(result) == 0:
+        # all empties -> check for bool to not coerce to float
+        kinds = {obj.dtype.kind for obj in to_concat_no_proxy}
+        if len(kinds) != 1:
+            if "b" in kinds:
+                result = result.astype(object)
+    return result

venv/lib/python3.10/site-packages/pandas/core/internals/base.py

@@ -0,0 +1,407 @@
+"""
+Base class for the internal managers. Both BlockManager and ArrayManager
+inherit from this class.
+"""
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Literal,
+    cast,
+    final,
+)
+
+import numpy as np
+
+from pandas._config import (
+    using_copy_on_write,
+    warn_copy_on_write,
+)
+
+from pandas._libs import (
+    algos as libalgos,
+    lib,
+)
+from pandas.errors import AbstractMethodError
+from pandas.util._validators import validate_bool_kwarg
+
+from pandas.core.dtypes.cast import (
+    find_common_type,
+    np_can_hold_element,
+)
+from pandas.core.dtypes.dtypes import (
+    ExtensionDtype,
+    SparseDtype,
+)
+
+from pandas.core.base import PandasObject
+from pandas.core.construction import extract_array
+from pandas.core.indexes.api import (
+    Index,
+    default_index,
+)
+
+if TYPE_CHECKING:
+    from pandas._typing import (
+        ArrayLike,
+        AxisInt,
+        DtypeObj,
+        Self,
+        Shape,
+    )
+
+
+class _AlreadyWarned:
+    def __init__(self):
+        # This class is used on the manager level to the block level to
+        # ensure that we warn only once. The block method can update the
+        # warned_already option without returning a value to keep the
+        # interface consistent. This is only a temporary solution for
+        # CoW warnings.
+        self.warned_already = False
+
+
+class DataManager(PandasObject):
+    # TODO share more methods/attributes
+
+    axes: list[Index]
+
+    @property
+    def items(self) -> Index:
+        raise AbstractMethodError(self)
+
+    @final
+    def __len__(self) -> int:
+        return len(self.items)
+
+    @property
+    def ndim(self) -> int:
+        return len(self.axes)
+
+    @property
+    def shape(self) -> Shape:
+        return tuple(len(ax) for ax in self.axes)
+
+    @final
+    def _validate_set_axis(self, axis: AxisInt, new_labels: Index) -> None:
+        # Caller is responsible for ensuring we have an Index object.
+        old_len = len(self.axes[axis])
+        new_len = len(new_labels)
+
+        if axis == 1 and len(self.items) == 0:
+            # If we are setting the index on a DataFrame with no columns,
+            #  it is OK to change the length.
+            pass
+
+        elif new_len != old_len:
+            raise ValueError(
+                f"Length mismatch: Expected axis has {old_len} elements, new "
+                f"values have {new_len} elements"
+            )
+
+    def reindex_indexer(
+        self,
+        new_axis,
+        indexer,
+        axis: AxisInt,
+        fill_value=None,
+        allow_dups: bool = False,
+        copy: bool = True,
+        only_slice: bool = False,
+    ) -> Self:
+        raise AbstractMethodError(self)
+
+    @final
+    def reindex_axis(
+        self,
+        new_index: Index,
+        axis: AxisInt,
+        fill_value=None,
+        only_slice: bool = False,
+    ) -> Self:
+        """
+        Conform data manager to new index.
+        """
+        new_index, indexer = self.axes[axis].reindex(new_index)
+
+        return self.reindex_indexer(
+            new_index,
+            indexer,
+            axis=axis,
+            fill_value=fill_value,
+            copy=False,
+            only_slice=only_slice,
+        )
+
+    def _equal_values(self, other: Self) -> bool:
+        """
+        To be implemented by the subclasses. Only check the column values
+        assuming shape and indexes have already been checked.
+        """
+        raise AbstractMethodError(self)
+
+    @final
+    def equals(self, other: object) -> bool:
+        """
+        Implementation for DataFrame.equals
+        """
+        if not isinstance(other, type(self)):
+            return False
+
+        self_axes, other_axes = self.axes, other.axes
+        if len(self_axes) != len(other_axes):
+            return False
+        if not all(ax1.equals(ax2) for ax1, ax2 in zip(self_axes, other_axes)):
+            return False
+
+        return self._equal_values(other)
+
+    def apply(
+        self,
+        f,
+        align_keys: list[str] | None = None,
+        **kwargs,
+    ) -> Self:
+        raise AbstractMethodError(self)
+
+    def apply_with_block(
+        self,
+        f,
+        align_keys: list[str] | None = None,
+        **kwargs,
+    ) -> Self:
+        raise AbstractMethodError(self)
+
+    @final
+    def isna(self, func) -> Self:
+        return self.apply("apply", func=func)
+
+    @final
+    def fillna(self, value, limit: int | None, inplace: bool, downcast) -> Self:
+        if limit is not None:
+            # Do this validation even if we go through one of the no-op paths
+            limit = libalgos.validate_limit(None, limit=limit)
+
+        return self.apply_with_block(
+            "fillna",
+            value=value,
+            limit=limit,
+            inplace=inplace,
+            downcast=downcast,
+            using_cow=using_copy_on_write(),
+            already_warned=_AlreadyWarned(),
+        )
+
+    @final
+    def where(self, other, cond, align: bool) -> Self:
+        if align:
+            align_keys = ["other", "cond"]
+        else:
+            align_keys = ["cond"]
+            other = extract_array(other, extract_numpy=True)
+
+        return self.apply_with_block(
+            "where",
+            align_keys=align_keys,
+            other=other,
+            cond=cond,
+            using_cow=using_copy_on_write(),
+        )
+
+    @final
+    def putmask(self, mask, new, align: bool = True, warn: bool = True) -> Self:
+        if align:
+            align_keys = ["new", "mask"]
+        else:
+            align_keys = ["mask"]
+            new = extract_array(new, extract_numpy=True)
+
+        already_warned = None
+        if warn_copy_on_write():
+            already_warned = _AlreadyWarned()
+            if not warn:
+                already_warned.warned_already = True
+
+        return self.apply_with_block(
+            "putmask",
+            align_keys=align_keys,
+            mask=mask,
+            new=new,
+            using_cow=using_copy_on_write(),
+            already_warned=already_warned,
+        )
+
+    @final
+    def round(self, decimals: int, using_cow: bool = False) -> Self:
+        return self.apply_with_block(
+            "round",
+            decimals=decimals,
+            using_cow=using_cow,
+        )
+
+    @final
+    def replace(self, to_replace, value, inplace: bool) -> Self:
+        inplace = validate_bool_kwarg(inplace, "inplace")
+        # NDFrame.replace ensures the not-is_list_likes here
+        assert not lib.is_list_like(to_replace)
+        assert not lib.is_list_like(value)
+        return self.apply_with_block(
+            "replace",
+            to_replace=to_replace,
+            value=value,
+            inplace=inplace,
+            using_cow=using_copy_on_write(),
+            already_warned=_AlreadyWarned(),
+        )
+
+    @final
+    def replace_regex(self, **kwargs) -> Self:
+        return self.apply_with_block(
+            "_replace_regex",
+            **kwargs,
+            using_cow=using_copy_on_write(),
+            already_warned=_AlreadyWarned(),
+        )
+
+    @final
+    def replace_list(
+        self,
+        src_list: list[Any],
+        dest_list: list[Any],
+        inplace: bool = False,
+        regex: bool = False,
+    ) -> Self:
+        """do a list replace"""
+        inplace = validate_bool_kwarg(inplace, "inplace")
+
+        bm = self.apply_with_block(
+            "replace_list",
+            src_list=src_list,
+            dest_list=dest_list,
+            inplace=inplace,
+            regex=regex,
+            using_cow=using_copy_on_write(),
+            already_warned=_AlreadyWarned(),
+        )
+        bm._consolidate_inplace()
+        return bm
+
+    def interpolate(self, inplace: bool, **kwargs) -> Self:
+        return self.apply_with_block(
+            "interpolate",
+            inplace=inplace,
+            **kwargs,
+            using_cow=using_copy_on_write(),
+            already_warned=_AlreadyWarned(),
+        )
+
+    def pad_or_backfill(self, inplace: bool, **kwargs) -> Self:
+        return self.apply_with_block(
+            "pad_or_backfill",
+            inplace=inplace,
+            **kwargs,
+            using_cow=using_copy_on_write(),
+            already_warned=_AlreadyWarned(),
+        )
+
+    def shift(self, periods: int, fill_value) -> Self:
+        if fill_value is lib.no_default:
+            fill_value = None
+
+        return self.apply_with_block("shift", periods=periods, fill_value=fill_value)
+
+    # --------------------------------------------------------------------
+    # Consolidation: No-ops for all but BlockManager
+
+    def is_consolidated(self) -> bool:
+        return True
+
+    def consolidate(self) -> Self:
+        return self
+
+    def _consolidate_inplace(self) -> None:
+        return
+
+
+class SingleDataManager(DataManager):
+    @property
+    def ndim(self) -> Literal[1]:
+        return 1
+
+    @final
+    @property
+    def array(self) -> ArrayLike:
+        """
+        Quick access to the backing array of the Block or SingleArrayManager.
+        """
+        # error: "SingleDataManager" has no attribute "arrays"; maybe "array"
+        return self.arrays[0]  # type: ignore[attr-defined]
+
+    def setitem_inplace(self, indexer, value, warn: bool = True) -> None:
+        """
+        Set values with indexer.
+
+        For Single[Block/Array]Manager, this backs s[indexer] = value
+
+        This is an inplace version of `setitem()`, mutating the manager/values
+        in place, not returning a new Manager (and Block), and thus never changing
+        the dtype.
+        """
+        arr = self.array
+
+        # EAs will do this validation in their own __setitem__ methods.
+        if isinstance(arr, np.ndarray):
+            # Note: checking for ndarray instead of np.dtype means we exclude
+            #  dt64/td64, which do their own validation.
+            value = np_can_hold_element(arr.dtype, value)
+
+        if isinstance(value, np.ndarray) and value.ndim == 1 and len(value) == 1:
+            # NumPy 1.25 deprecation: https://github.com/numpy/numpy/pull/10615
+            value = value[0, ...]
+
+        arr[indexer] = value
+
+    def grouped_reduce(self, func):
+        arr = self.array
+        res = func(arr)
+        index = default_index(len(res))
+
+        mgr = type(self).from_array(res, index)
+        return mgr
+
+    @classmethod
+    def from_array(cls, arr: ArrayLike, index: Index):
+        raise AbstractMethodError(cls)
+
+
+def interleaved_dtype(dtypes: list[DtypeObj]) -> DtypeObj | None:
+    """
+    Find the common dtype for `blocks`.
+
+    Parameters
+    ----------
+    blocks : List[DtypeObj]
+
+    Returns
+    -------
+    dtype : np.dtype, ExtensionDtype, or None
+        None is returned when `blocks` is empty.
+    """
+    if not len(dtypes):
+        return None
+
+    return find_common_type(dtypes)
+
+
+def ensure_np_dtype(dtype: DtypeObj) -> np.dtype:
+    # TODO: https://github.com/pandas-dev/pandas/issues/22791
+    # Give EAs some input on what happens here. Sparse needs this.
+    if isinstance(dtype, SparseDtype):
+        dtype = dtype.subtype
+        dtype = cast(np.dtype, dtype)
+    elif isinstance(dtype, ExtensionDtype):
+        dtype = np.dtype("object")
+    elif dtype == np.dtype(str):
+        dtype = np.dtype("object")
+    return dtype

venv/lib/python3.10/site-packages/pandas/core/internals/concat.py

@@ -0,0 +1,598 @@
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    cast,
+)
+import warnings
+
+import numpy as np
+
+from pandas._libs import (
+    NaT,
+    algos as libalgos,
+    internals as libinternals,
+    lib,
+)
+from pandas._libs.missing import NA
+from pandas.util._decorators import cache_readonly
+from pandas.util._exceptions import find_stack_level
+
+from pandas.core.dtypes.cast import (
+    ensure_dtype_can_hold_na,
+    find_common_type,
+)
+from pandas.core.dtypes.common import (
+    is_1d_only_ea_dtype,
+    is_scalar,
+    needs_i8_conversion,
+)
+from pandas.core.dtypes.concat import concat_compat
+from pandas.core.dtypes.dtypes import (
+    ExtensionDtype,
+    SparseDtype,
+)
+from pandas.core.dtypes.missing import (
+    is_valid_na_for_dtype,
+    isna,
+    isna_all,
+)
+
+from pandas.core.construction import ensure_wrapped_if_datetimelike
+from pandas.core.internals.array_manager import ArrayManager
+from pandas.core.internals.blocks import (
+    ensure_block_shape,
+    new_block_2d,
+)
+from pandas.core.internals.managers import (
+    BlockManager,
+    make_na_array,
+)
+
+if TYPE_CHECKING:
+    from collections.abc import Sequence
+
+    from pandas._typing import (
+        ArrayLike,
+        AxisInt,
+        DtypeObj,
+        Manager2D,
+        Shape,
+    )
+
+    from pandas import Index
+    from pandas.core.internals.blocks import (
+        Block,
+        BlockPlacement,
+    )
+
+
+def _concatenate_array_managers(
+    mgrs: list[ArrayManager], axes: list[Index], concat_axis: AxisInt
+) -> Manager2D:
+    """
+    Concatenate array managers into one.
+
+    Parameters
+    ----------
+    mgrs_indexers : list of (ArrayManager, {axis: indexer,...}) tuples
+    axes : list of Index
+    concat_axis : int
+
+    Returns
+    -------
+    ArrayManager
+    """
+    if concat_axis == 1:
+        return mgrs[0].concat_vertical(mgrs, axes)
+    else:
+        # concatting along the columns -> combine reindexed arrays in a single manager
+        assert concat_axis == 0
+        return mgrs[0].concat_horizontal(mgrs, axes)
+
+
+def concatenate_managers(
+    mgrs_indexers, axes: list[Index], concat_axis: AxisInt, copy: bool
+) -> Manager2D:
+    """
+    Concatenate block managers into one.
+
+    Parameters
+    ----------
+    mgrs_indexers : list of (BlockManager, {axis: indexer,...}) tuples
+    axes : list of Index
+    concat_axis : int
+    copy : bool
+
+    Returns
+    -------
+    BlockManager
+    """
+
+    needs_copy = copy and concat_axis == 0
+
+    # TODO(ArrayManager) this assumes that all managers are of the same type
+    if isinstance(mgrs_indexers[0][0], ArrayManager):
+        mgrs = _maybe_reindex_columns_na_proxy(axes, mgrs_indexers, needs_copy)
+        # error: Argument 1 to "_concatenate_array_managers" has incompatible
+        # type "List[BlockManager]"; expected "List[Union[ArrayManager,
+        # SingleArrayManager, BlockManager, SingleBlockManager]]"
+        return _concatenate_array_managers(
+            mgrs, axes, concat_axis  # type: ignore[arg-type]
+        )
+
+    # Assertions disabled for performance
+    # for tup in mgrs_indexers:
+    #    # caller is responsible for ensuring this
+    #    indexers = tup[1]
+    #    assert concat_axis not in indexers
+
+    if concat_axis == 0:
+        mgrs = _maybe_reindex_columns_na_proxy(axes, mgrs_indexers, needs_copy)
+        return mgrs[0].concat_horizontal(mgrs, axes)
+
+    if len(mgrs_indexers) > 0 and mgrs_indexers[0][0].nblocks > 0:
+        first_dtype = mgrs_indexers[0][0].blocks[0].dtype
+        if first_dtype in [np.float64, np.float32]:
+            # TODO: support more dtypes here.  This will be simpler once
+            #  JoinUnit.is_na behavior is deprecated.
+            if (
+                all(_is_homogeneous_mgr(mgr, first_dtype) for mgr, _ in mgrs_indexers)
+                and len(mgrs_indexers) > 1
+            ):
+                # Fastpath!
+                # Length restriction is just to avoid having to worry about 'copy'
+                shape = tuple(len(x) for x in axes)
+                nb = _concat_homogeneous_fastpath(mgrs_indexers, shape, first_dtype)
+                return BlockManager((nb,), axes)
+
+    mgrs = _maybe_reindex_columns_na_proxy(axes, mgrs_indexers, needs_copy)
+
+    if len(mgrs) == 1:
+        mgr = mgrs[0]
+        out = mgr.copy(deep=False)
+        out.axes = axes
+        return out
+
+    concat_plan = _get_combined_plan(mgrs)
+
+    blocks = []
+    values: ArrayLike
+
+    for placement, join_units in concat_plan:
+        unit = join_units[0]
+        blk = unit.block
+
+        if _is_uniform_join_units(join_units):
+            vals = [ju.block.values for ju in join_units]
+
+            if not blk.is_extension:
+                # _is_uniform_join_units ensures a single dtype, so
+                #  we can use np.concatenate, which is more performant
+                #  than concat_compat
+                # error: Argument 1 to "concatenate" has incompatible type
+                # "List[Union[ndarray[Any, Any], ExtensionArray]]";
+                # expected "Union[_SupportsArray[dtype[Any]],
+                # _NestedSequence[_SupportsArray[dtype[Any]]]]"
+                values = np.concatenate(vals, axis=1)  # type: ignore[arg-type]
+            elif is_1d_only_ea_dtype(blk.dtype):
+                # TODO(EA2D): special-casing not needed with 2D EAs
+                values = concat_compat(vals, axis=0, ea_compat_axis=True)
+                values = ensure_block_shape(values, ndim=2)
+            else:
+                values = concat_compat(vals, axis=1)
+
+            values = ensure_wrapped_if_datetimelike(values)
+
+            fastpath = blk.values.dtype == values.dtype
+        else:
+            values = _concatenate_join_units(join_units, copy=copy)
+            fastpath = False
+
+        if fastpath:
+            b = blk.make_block_same_class(values, placement=placement)
+        else:
+            b = new_block_2d(values, placement=placement)
+
+        blocks.append(b)
+
+    return BlockManager(tuple(blocks), axes)
+
+
+def _maybe_reindex_columns_na_proxy(
+    axes: list[Index],
+    mgrs_indexers: list[tuple[BlockManager, dict[int, np.ndarray]]],
+    needs_copy: bool,
+) -> list[BlockManager]:
+    """
+    Reindex along columns so that all of the BlockManagers being concatenated
+    have matching columns.
+
+    Columns added in this reindexing have dtype=np.void, indicating they
+    should be ignored when choosing a column's final dtype.
+    """
+    new_mgrs = []
+
+    for mgr, indexers in mgrs_indexers:
+        # For axis=0 (i.e. columns) we use_na_proxy and only_slice, so this
+        #  is a cheap reindexing.
+        for i, indexer in indexers.items():
+            mgr = mgr.reindex_indexer(
+                axes[i],
+                indexers[i],
+                axis=i,
+                copy=False,
+                only_slice=True,  # only relevant for i==0
+                allow_dups=True,
+                use_na_proxy=True,  # only relevant for i==0
+            )
+        if needs_copy and not indexers:
+            mgr = mgr.copy()
+
+        new_mgrs.append(mgr)
+    return new_mgrs
+
+
+def _is_homogeneous_mgr(mgr: BlockManager, first_dtype: DtypeObj) -> bool:
+    """
+    Check if this Manager can be treated as a single ndarray.
+    """
+    if mgr.nblocks != 1:
+        return False
+    blk = mgr.blocks[0]
+    if not (blk.mgr_locs.is_slice_like and blk.mgr_locs.as_slice.step == 1):
+        return False
+
+    return blk.dtype == first_dtype
+
+
+def _concat_homogeneous_fastpath(
+    mgrs_indexers, shape: Shape, first_dtype: np.dtype
+) -> Block:
+    """
+    With single-Block managers with homogeneous dtypes (that can already hold nan),
+    we avoid [...]
+    """
+    # assumes
+    #  all(_is_homogeneous_mgr(mgr, first_dtype) for mgr, _ in in mgrs_indexers)
+
+    if all(not indexers for _, indexers in mgrs_indexers):
+        # https://github.com/pandas-dev/pandas/pull/52685#issuecomment-1523287739
+        arrs = [mgr.blocks[0].values.T for mgr, _ in mgrs_indexers]
+        arr = np.concatenate(arrs).T
+        bp = libinternals.BlockPlacement(slice(shape[0]))
+        nb = new_block_2d(arr, bp)
+        return nb
+
+    arr = np.empty(shape, dtype=first_dtype)
+
+    if first_dtype == np.float64:
+        take_func = libalgos.take_2d_axis0_float64_float64
+    else:
+        take_func = libalgos.take_2d_axis0_float32_float32
+
+    start = 0
+    for mgr, indexers in mgrs_indexers:
+        mgr_len = mgr.shape[1]
+        end = start + mgr_len
+
+        if 0 in indexers:
+            take_func(
+                mgr.blocks[0].values,
+                indexers[0],
+                arr[:, start:end],
+            )
+        else:
+            # No reindexing necessary, we can copy values directly
+            arr[:, start:end] = mgr.blocks[0].values
+
+        start += mgr_len
+
+    bp = libinternals.BlockPlacement(slice(shape[0]))
+    nb = new_block_2d(arr, bp)
+    return nb
+
+
+def _get_combined_plan(
+    mgrs: list[BlockManager],
+) -> list[tuple[BlockPlacement, list[JoinUnit]]]:
+    plan = []
+
+    max_len = mgrs[0].shape[0]
+
+    blknos_list = [mgr.blknos for mgr in mgrs]
+    pairs = libinternals.get_concat_blkno_indexers(blknos_list)
+    for ind, (blknos, bp) in enumerate(pairs):
+        # assert bp.is_slice_like
+        # assert len(bp) > 0
+
+        units_for_bp = []
+        for k, mgr in enumerate(mgrs):
+            blkno = blknos[k]
+
+            nb = _get_block_for_concat_plan(mgr, bp, blkno, max_len=max_len)
+            unit = JoinUnit(nb)
+            units_for_bp.append(unit)
+
+        plan.append((bp, units_for_bp))
+
+    return plan
+
+
+def _get_block_for_concat_plan(
+    mgr: BlockManager, bp: BlockPlacement, blkno: int, *, max_len: int
+) -> Block:
+    blk = mgr.blocks[blkno]
+    # Assertions disabled for performance:
+    #  assert bp.is_slice_like
+    #  assert blkno != -1
+    #  assert (mgr.blknos[bp] == blkno).all()
+
+    if len(bp) == len(blk.mgr_locs) and (
+        blk.mgr_locs.is_slice_like and blk.mgr_locs.as_slice.step == 1
+    ):
+        nb = blk
+    else:
+        ax0_blk_indexer = mgr.blklocs[bp.indexer]
+
+        slc = lib.maybe_indices_to_slice(ax0_blk_indexer, max_len)
+        # TODO: in all extant test cases 2023-04-08 we have a slice here.
+        #  Will this always be the case?
+        if isinstance(slc, slice):
+            nb = blk.slice_block_columns(slc)
+        else:
+            nb = blk.take_block_columns(slc)
+
+    # assert nb.shape == (len(bp), mgr.shape[1])
+    return nb
+
+
+class JoinUnit:
+    def __init__(self, block: Block) -> None:
+        self.block = block
+
+    def __repr__(self) -> str:
+        return f"{type(self).__name__}({repr(self.block)})"
+
+    def _is_valid_na_for(self, dtype: DtypeObj) -> bool:
+        """
+        Check that we are all-NA of a type/dtype that is compatible with this dtype.
+        Augments `self.is_na` with an additional check of the type of NA values.
+        """
+        if not self.is_na:
+            return False
+
+        blk = self.block
+        if blk.dtype.kind == "V":
+            return True
+
+        if blk.dtype == object:
+            values = blk.values
+            return all(is_valid_na_for_dtype(x, dtype) for x in values.ravel(order="K"))
+
+        na_value = blk.fill_value
+        if na_value is NaT and blk.dtype != dtype:
+            # e.g. we are dt64 and other is td64
+            # fill_values match but we should not cast blk.values to dtype
+            # TODO: this will need updating if we ever have non-nano dt64/td64
+            return False
+
+        if na_value is NA and needs_i8_conversion(dtype):
+            # FIXME: kludge; test_append_empty_frame_with_timedelta64ns_nat
+            #  e.g. blk.dtype == "Int64" and dtype is td64, we dont want
+            #  to consider these as matching
+            return False
+
+        # TODO: better to use can_hold_element?
+        return is_valid_na_for_dtype(na_value, dtype)
+
+    @cache_readonly
+    def is_na(self) -> bool:
+        blk = self.block
+        if blk.dtype.kind == "V":
+            return True
+
+        if not blk._can_hold_na:
+            return False
+
+        values = blk.values
+        if values.size == 0:
+            # GH#39122 this case will return False once deprecation is enforced
+            return True
+
+        if isinstance(values.dtype, SparseDtype):
+            return False
+
+        if values.ndim == 1:
+            # TODO(EA2D): no need for special case with 2D EAs
+            val = values[0]
+            if not is_scalar(val) or not isna(val):
+                # ideally isna_all would do this short-circuiting
+                return False
+            return isna_all(values)
+        else:
+            val = values[0][0]
+            if not is_scalar(val) or not isna(val):
+                # ideally isna_all would do this short-circuiting
+                return False
+            return all(isna_all(row) for row in values)
+
+    @cache_readonly
+    def is_na_after_size_and_isna_all_deprecation(self) -> bool:
+        """
+        Will self.is_na be True after values.size == 0 deprecation and isna_all
+        deprecation are enforced?
+        """
+        blk = self.block
+        if blk.dtype.kind == "V":
+            return True
+        return False
+
+    def get_reindexed_values(self, empty_dtype: DtypeObj, upcasted_na) -> ArrayLike:
+        values: ArrayLike
+
+        if upcasted_na is None and self.block.dtype.kind != "V":
+            # No upcasting is necessary
+            return self.block.values
+        else:
+            fill_value = upcasted_na
+
+            if self._is_valid_na_for(empty_dtype):
+                # note: always holds when self.block.dtype.kind == "V"
+                blk_dtype = self.block.dtype
+
+                if blk_dtype == np.dtype("object"):
+                    # we want to avoid filling with np.nan if we are
+                    # using None; we already know that we are all
+                    # nulls
+                    values = cast(np.ndarray, self.block.values)
+                    if values.size and values[0, 0] is None:
+                        fill_value = None
+
+                return make_na_array(empty_dtype, self.block.shape, fill_value)
+
+            return self.block.values
+
+
+def _concatenate_join_units(join_units: list[JoinUnit], copy: bool) -> ArrayLike:
+    """
+    Concatenate values from several join units along axis=1.
+    """
+    empty_dtype, empty_dtype_future = _get_empty_dtype(join_units)
+
+    has_none_blocks = any(unit.block.dtype.kind == "V" for unit in join_units)
+    upcasted_na = _dtype_to_na_value(empty_dtype, has_none_blocks)
+
+    to_concat = [
+        ju.get_reindexed_values(empty_dtype=empty_dtype, upcasted_na=upcasted_na)
+        for ju in join_units
+    ]
+
+    if any(is_1d_only_ea_dtype(t.dtype) for t in to_concat):
+        # TODO(EA2D): special case not needed if all EAs used HybridBlocks
+
+        # error: No overload variant of "__getitem__" of "ExtensionArray" matches
+        # argument type "Tuple[int, slice]"
+        to_concat = [
+            t
+            if is_1d_only_ea_dtype(t.dtype)
+            else t[0, :]  # type: ignore[call-overload]
+            for t in to_concat
+        ]
+        concat_values = concat_compat(to_concat, axis=0, ea_compat_axis=True)
+        concat_values = ensure_block_shape(concat_values, 2)
+
+    else:
+        concat_values = concat_compat(to_concat, axis=1)
+
+    if empty_dtype != empty_dtype_future:
+        if empty_dtype == concat_values.dtype:
+            # GH#39122, GH#40893
+            warnings.warn(
+                "The behavior of DataFrame concatenation with empty or all-NA "
+                "entries is deprecated. In a future version, this will no longer "
+                "exclude empty or all-NA columns when determining the result dtypes. "
+                "To retain the old behavior, exclude the relevant entries before "
+                "the concat operation.",
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
+    return concat_values
+
+
+def _dtype_to_na_value(dtype: DtypeObj, has_none_blocks: bool):
+    """
+    Find the NA value to go with this dtype.
+    """
+    if isinstance(dtype, ExtensionDtype):
+        return dtype.na_value
+    elif dtype.kind in "mM":
+        return dtype.type("NaT")
+    elif dtype.kind in "fc":
+        return dtype.type("NaN")
+    elif dtype.kind == "b":
+        # different from missing.na_value_for_dtype
+        return None
+    elif dtype.kind in "iu":
+        if not has_none_blocks:
+            # different from missing.na_value_for_dtype
+            return None
+        return np.nan
+    elif dtype.kind == "O":
+        return np.nan
+    raise NotImplementedError
+
+
+def _get_empty_dtype(join_units: Sequence[JoinUnit]) -> tuple[DtypeObj, DtypeObj]:
+    """
+    Return dtype and N/A values to use when concatenating specified units.
+
+    Returned N/A value may be None which means there was no casting involved.
+
+    Returns
+    -------
+    dtype
+    """
+    if lib.dtypes_all_equal([ju.block.dtype for ju in join_units]):
+        empty_dtype = join_units[0].block.dtype
+        return empty_dtype, empty_dtype
+
+    has_none_blocks = any(unit.block.dtype.kind == "V" for unit in join_units)
+
+    dtypes = [unit.block.dtype for unit in join_units if not unit.is_na]
+    if not len(dtypes):
+        dtypes = [
+            unit.block.dtype for unit in join_units if unit.block.dtype.kind != "V"
+        ]
+
+    dtype = find_common_type(dtypes)
+    if has_none_blocks:
+        dtype = ensure_dtype_can_hold_na(dtype)
+
+    dtype_future = dtype
+    if len(dtypes) != len(join_units):
+        dtypes_future = [
+            unit.block.dtype
+            for unit in join_units
+            if not unit.is_na_after_size_and_isna_all_deprecation
+        ]
+        if not len(dtypes_future):
+            dtypes_future = [
+                unit.block.dtype for unit in join_units if unit.block.dtype.kind != "V"
+            ]
+
+        if len(dtypes) != len(dtypes_future):
+            dtype_future = find_common_type(dtypes_future)
+            if has_none_blocks:
+                dtype_future = ensure_dtype_can_hold_na(dtype_future)
+
+    return dtype, dtype_future
+
+
+def _is_uniform_join_units(join_units: list[JoinUnit]) -> bool:
+    """
+    Check if the join units consist of blocks of uniform type that can
+    be concatenated using Block.concat_same_type instead of the generic
+    _concatenate_join_units (which uses `concat_compat`).
+
+    """
+    first = join_units[0].block
+    if first.dtype.kind == "V":
+        return False
+    return (
+        # exclude cases where a) ju.block is None or b) we have e.g. Int64+int64
+        all(type(ju.block) is type(first) for ju in join_units)
+        and
+        # e.g. DatetimeLikeBlock can be dt64 or td64, but these are not uniform
+        all(
+            ju.block.dtype == first.dtype
+            # GH#42092 we only want the dtype_equal check for non-numeric blocks
+            #  (for now, may change but that would need a deprecation)
+            or ju.block.dtype.kind in "iub"
+            for ju in join_units
+        )
+        and
+        # no blocks that would get missing values (can lead to type upcasts)
+        # unless we're an extension dtype.
+        all(not ju.is_na or ju.block.is_extension for ju in join_units)
+    )

venv/lib/python3.10/site-packages/pandas/core/internals/construction.py

@@ -0,0 +1,1072 @@
+"""
+Functions for preparing various inputs passed to the DataFrame or Series
+constructors before passing them to a BlockManager.
+"""
+from __future__ import annotations
+
+from collections import abc
+from typing import (
+    TYPE_CHECKING,
+    Any,
+)
+
+import numpy as np
+from numpy import ma
+
+from pandas._config import using_pyarrow_string_dtype
+
+from pandas._libs import lib
+
+from pandas.core.dtypes.astype import astype_is_view
+from pandas.core.dtypes.cast import (
+    construct_1d_arraylike_from_scalar,
+    dict_compat,
+    maybe_cast_to_datetime,
+    maybe_convert_platform,
+    maybe_infer_to_datetimelike,
+)
+from pandas.core.dtypes.common import (
+    is_1d_only_ea_dtype,
+    is_integer_dtype,
+    is_list_like,
+    is_named_tuple,
+    is_object_dtype,
+)
+from pandas.core.dtypes.dtypes import ExtensionDtype
+from pandas.core.dtypes.generic import (
+    ABCDataFrame,
+    ABCSeries,
+)
+
+from pandas.core import (
+    algorithms,
+    common as com,
+)
+from pandas.core.arrays import ExtensionArray
+from pandas.core.arrays.string_ import StringDtype
+from pandas.core.construction import (
+    array as pd_array,
+    ensure_wrapped_if_datetimelike,
+    extract_array,
+    range_to_ndarray,
+    sanitize_array,
+)
+from pandas.core.indexes.api import (
+    DatetimeIndex,
+    Index,
+    TimedeltaIndex,
+    default_index,
+    ensure_index,
+    get_objs_combined_axis,
+    union_indexes,
+)
+from pandas.core.internals.array_manager import (
+    ArrayManager,
+    SingleArrayManager,
+)
+from pandas.core.internals.blocks import (
+    BlockPlacement,
+    ensure_block_shape,
+    new_block,
+    new_block_2d,
+)
+from pandas.core.internals.managers import (
+    BlockManager,
+    SingleBlockManager,
+    create_block_manager_from_blocks,
+    create_block_manager_from_column_arrays,
+)
+
+if TYPE_CHECKING:
+    from collections.abc import (
+        Hashable,
+        Sequence,
+    )
+
+    from pandas._typing import (
+        ArrayLike,
+        DtypeObj,
+        Manager,
+        npt,
+    )
+# ---------------------------------------------------------------------
+# BlockManager Interface
+
+
+def arrays_to_mgr(
+    arrays,
+    columns: Index,
+    index,
+    *,
+    dtype: DtypeObj | None = None,
+    verify_integrity: bool = True,
+    typ: str | None = None,
+    consolidate: bool = True,
+) -> Manager:
+    """
+    Segregate Series based on type and coerce into matrices.
+
+    Needs to handle a lot of exceptional cases.
+    """
+    if verify_integrity:
+        # figure out the index, if necessary
+        if index is None:
+            index = _extract_index(arrays)
+        else:
+            index = ensure_index(index)
+
+        # don't force copy because getting jammed in an ndarray anyway
+        arrays, refs = _homogenize(arrays, index, dtype)
+        # _homogenize ensures
+        #  - all(len(x) == len(index) for x in arrays)
+        #  - all(x.ndim == 1 for x in arrays)
+        #  - all(isinstance(x, (np.ndarray, ExtensionArray)) for x in arrays)
+        #  - all(type(x) is not NumpyExtensionArray for x in arrays)
+
+    else:
+        index = ensure_index(index)
+        arrays = [extract_array(x, extract_numpy=True) for x in arrays]
+        # with _from_arrays, the passed arrays should never be Series objects
+        refs = [None] * len(arrays)
+
+        # Reached via DataFrame._from_arrays; we do minimal validation here
+        for arr in arrays:
+            if (
+                not isinstance(arr, (np.ndarray, ExtensionArray))
+                or arr.ndim != 1
+                or len(arr) != len(index)
+            ):
+                raise ValueError(
+                    "Arrays must be 1-dimensional np.ndarray or ExtensionArray "
+                    "with length matching len(index)"
+                )
+
+    columns = ensure_index(columns)
+    if len(columns) != len(arrays):
+        raise ValueError("len(arrays) must match len(columns)")
+
+    # from BlockManager perspective
+    axes = [columns, index]
+
+    if typ == "block":
+        return create_block_manager_from_column_arrays(
+            arrays, axes, consolidate=consolidate, refs=refs
+        )
+    elif typ == "array":
+        return ArrayManager(arrays, [index, columns])
+    else:
+        raise ValueError(f"'typ' needs to be one of {{'block', 'array'}}, got '{typ}'")
+
+
+def rec_array_to_mgr(
+    data: np.rec.recarray | np.ndarray,
+    index,
+    columns,
+    dtype: DtypeObj | None,
+    copy: bool,
+    typ: str,
+) -> Manager:
+    """
+    Extract from a masked rec array and create the manager.
+    """
+    # essentially process a record array then fill it
+    fdata = ma.getdata(data)
+    if index is None:
+        index = default_index(len(fdata))
+    else:
+        index = ensure_index(index)
+
+    if columns is not None:
+        columns = ensure_index(columns)
+    arrays, arr_columns = to_arrays(fdata, columns)
+
+    # create the manager
+
+    arrays, arr_columns = reorder_arrays(arrays, arr_columns, columns, len(index))
+    if columns is None:
+        columns = arr_columns
+
+    mgr = arrays_to_mgr(arrays, columns, index, dtype=dtype, typ=typ)
+
+    if copy:
+        mgr = mgr.copy()
+    return mgr
+
+
+def mgr_to_mgr(mgr, typ: str, copy: bool = True) -> Manager:
+    """
+    Convert to specific type of Manager. Does not copy if the type is already
+    correct. Does not guarantee a copy otherwise. `copy` keyword only controls
+    whether conversion from Block->ArrayManager copies the 1D arrays.
+    """
+    new_mgr: Manager
+
+    if typ == "block":
+        if isinstance(mgr, BlockManager):
+            new_mgr = mgr
+        else:
+            if mgr.ndim == 2:
+                new_mgr = arrays_to_mgr(
+                    mgr.arrays, mgr.axes[0], mgr.axes[1], typ="block"
+                )
+            else:
+                new_mgr = SingleBlockManager.from_array(mgr.arrays[0], mgr.index)
+    elif typ == "array":
+        if isinstance(mgr, ArrayManager):
+            new_mgr = mgr
+        else:
+            if mgr.ndim == 2:
+                arrays = [mgr.iget_values(i) for i in range(len(mgr.axes[0]))]
+                if copy:
+                    arrays = [arr.copy() for arr in arrays]
+                new_mgr = ArrayManager(arrays, [mgr.axes[1], mgr.axes[0]])
+            else:
+                array = mgr.internal_values()
+                if copy:
+                    array = array.copy()
+                new_mgr = SingleArrayManager([array], [mgr.index])
+    else:
+        raise ValueError(f"'typ' needs to be one of {{'block', 'array'}}, got '{typ}'")
+    return new_mgr
+
+
+# ---------------------------------------------------------------------
+# DataFrame Constructor Interface
+
+
+def ndarray_to_mgr(
+    values, index, columns, dtype: DtypeObj | None, copy: bool, typ: str
+) -> Manager:
+    # used in DataFrame.__init__
+    # input must be a ndarray, list, Series, Index, ExtensionArray
+
+    if isinstance(values, ABCSeries):
+        if columns is None:
+            if values.name is not None:
+                columns = Index([values.name])
+        if index is None:
+            index = values.index
+        else:
+            values = values.reindex(index)
+
+        # zero len case (GH #2234)
+        if not len(values) and columns is not None and len(columns):
+            values = np.empty((0, 1), dtype=object)
+
+    # if the array preparation does a copy -> avoid this for ArrayManager,
+    # since the copy is done on conversion to 1D arrays
+    copy_on_sanitize = False if typ == "array" else copy
+
+    vdtype = getattr(values, "dtype", None)
+    refs = None
+    if is_1d_only_ea_dtype(vdtype) or is_1d_only_ea_dtype(dtype):
+        # GH#19157
+
+        if isinstance(values, (np.ndarray, ExtensionArray)) and values.ndim > 1:
+            # GH#12513 a EA dtype passed with a 2D array, split into
+            #  multiple EAs that view the values
+            # error: No overload variant of "__getitem__" of "ExtensionArray"
+            # matches argument type "Tuple[slice, int]"
+            values = [
+                values[:, n]  # type: ignore[call-overload]
+                for n in range(values.shape[1])
+            ]
+        else:
+            values = [values]
+
+        if columns is None:
+            columns = Index(range(len(values)))
+        else:
+            columns = ensure_index(columns)
+
+        return arrays_to_mgr(values, columns, index, dtype=dtype, typ=typ)
+
+    elif isinstance(vdtype, ExtensionDtype):
+        # i.e. Datetime64TZ, PeriodDtype; cases with is_1d_only_ea_dtype(vdtype)
+        #  are already caught above
+        values = extract_array(values, extract_numpy=True)
+        if copy:
+            values = values.copy()
+        if values.ndim == 1:
+            values = values.reshape(-1, 1)
+
+    elif isinstance(values, (ABCSeries, Index)):
+        if not copy_on_sanitize and (
+            dtype is None or astype_is_view(values.dtype, dtype)
+        ):
+            refs = values._references
+
+        if copy_on_sanitize:
+            values = values._values.copy()
+        else:
+            values = values._values
+
+        values = _ensure_2d(values)
+
+    elif isinstance(values, (np.ndarray, ExtensionArray)):
+        # drop subclass info
+        _copy = (
+            copy_on_sanitize
+            if (dtype is None or astype_is_view(values.dtype, dtype))
+            else False
+        )
+        values = np.array(values, copy=_copy)
+        values = _ensure_2d(values)
+
+    else:
+        # by definition an array here
+        # the dtypes will be coerced to a single dtype
+        values = _prep_ndarraylike(values, copy=copy_on_sanitize)
+
+    if dtype is not None and values.dtype != dtype:
+        # GH#40110 see similar check inside sanitize_array
+        values = sanitize_array(
+            values,
+            None,
+            dtype=dtype,
+            copy=copy_on_sanitize,
+            allow_2d=True,
+        )
+
+    # _prep_ndarraylike ensures that values.ndim == 2 at this point
+    index, columns = _get_axes(
+        values.shape[0], values.shape[1], index=index, columns=columns
+    )
+
+    _check_values_indices_shape_match(values, index, columns)
+
+    if typ == "array":
+        if issubclass(values.dtype.type, str):
+            values = np.array(values, dtype=object)
+
+        if dtype is None and is_object_dtype(values.dtype):
+            arrays = [
+                ensure_wrapped_if_datetimelike(
+                    maybe_infer_to_datetimelike(values[:, i])
+                )
+                for i in range(values.shape[1])
+            ]
+        else:
+            if lib.is_np_dtype(values.dtype, "mM"):
+                values = ensure_wrapped_if_datetimelike(values)
+            arrays = [values[:, i] for i in range(values.shape[1])]
+
+        if copy:
+            arrays = [arr.copy() for arr in arrays]
+
+        return ArrayManager(arrays, [index, columns], verify_integrity=False)
+
+    values = values.T
+
+    # if we don't have a dtype specified, then try to convert objects
+    # on the entire block; this is to convert if we have datetimelike's
+    # embedded in an object type
+    if dtype is None and is_object_dtype(values.dtype):
+        obj_columns = list(values)
+        maybe_datetime = [maybe_infer_to_datetimelike(x) for x in obj_columns]
+        # don't convert (and copy) the objects if no type inference occurs
+        if any(x is not y for x, y in zip(obj_columns, maybe_datetime)):
+            dvals_list = [ensure_block_shape(dval, 2) for dval in maybe_datetime]
+            block_values = [
+                new_block_2d(dvals_list[n], placement=BlockPlacement(n))
+                for n in range(len(dvals_list))
+            ]
+        else:
+            bp = BlockPlacement(slice(len(columns)))
+            nb = new_block_2d(values, placement=bp, refs=refs)
+            block_values = [nb]
+    elif dtype is None and values.dtype.kind == "U" and using_pyarrow_string_dtype():
+        dtype = StringDtype(storage="pyarrow_numpy")
+
+        obj_columns = list(values)
+        block_values = [
+            new_block(
+                dtype.construct_array_type()._from_sequence(data, dtype=dtype),
+                BlockPlacement(slice(i, i + 1)),
+                ndim=2,
+            )
+            for i, data in enumerate(obj_columns)
+        ]
+
+    else:
+        bp = BlockPlacement(slice(len(columns)))
+        nb = new_block_2d(values, placement=bp, refs=refs)
+        block_values = [nb]
+
+    if len(columns) == 0:
+        # TODO: check len(values) == 0?
+        block_values = []
+
+    return create_block_manager_from_blocks(
+        block_values, [columns, index], verify_integrity=False
+    )
+
+
+def _check_values_indices_shape_match(
+    values: np.ndarray, index: Index, columns: Index
+) -> None:
+    """
+    Check that the shape implied by our axes matches the actual shape of the
+    data.
+    """
+    if values.shape[1] != len(columns) or values.shape[0] != len(index):
+        # Could let this raise in Block constructor, but we get a more
+        #  helpful exception message this way.
+        if values.shape[0] == 0 < len(index):
+            raise ValueError("Empty data passed with indices specified.")
+
+        passed = values.shape
+        implied = (len(index), len(columns))
+        raise ValueError(f"Shape of passed values is {passed}, indices imply {implied}")
+
+
+def dict_to_mgr(
+    data: dict,
+    index,
+    columns,
+    *,
+    dtype: DtypeObj | None = None,
+    typ: str = "block",
+    copy: bool = True,
+) -> Manager:
+    """
+    Segregate Series based on type and coerce into matrices.
+    Needs to handle a lot of exceptional cases.
+
+    Used in DataFrame.__init__
+    """
+    arrays: Sequence[Any] | Series
+
+    if columns is not None:
+        from pandas.core.series import Series
+
+        arrays = Series(data, index=columns, dtype=object)
+        missing = arrays.isna()
+        if index is None:
+            # GH10856
+            # raise ValueError if only scalars in dict
+            index = _extract_index(arrays[~missing])
+        else:
+            index = ensure_index(index)
+
+        # no obvious "empty" int column
+        if missing.any() and not is_integer_dtype(dtype):
+            nan_dtype: DtypeObj
+
+            if dtype is not None:
+                # calling sanitize_array ensures we don't mix-and-match
+                #  NA dtypes
+                midxs = missing.values.nonzero()[0]
+                for i in midxs:
+                    arr = sanitize_array(arrays.iat[i], index, dtype=dtype)
+                    arrays.iat[i] = arr
+            else:
+                # GH#1783
+                nan_dtype = np.dtype("object")
+                val = construct_1d_arraylike_from_scalar(np.nan, len(index), nan_dtype)
+                nmissing = missing.sum()
+                if copy:
+                    rhs = [val] * nmissing
+                else:
+                    # GH#45369
+                    rhs = [val.copy() for _ in range(nmissing)]
+                arrays.loc[missing] = rhs
+
+        arrays = list(arrays)
+        columns = ensure_index(columns)
+
+    else:
+        keys = list(data.keys())
+        columns = Index(keys) if keys else default_index(0)
+        arrays = [com.maybe_iterable_to_list(data[k]) for k in keys]
+
+    if copy:
+        if typ == "block":
+            # We only need to copy arrays that will not get consolidated, i.e.
+            #  only EA arrays
+            arrays = [
+                x.copy()
+                if isinstance(x, ExtensionArray)
+                else x.copy(deep=True)
+                if (
+                    isinstance(x, Index)
+                    or isinstance(x, ABCSeries)
+                    and is_1d_only_ea_dtype(x.dtype)
+                )
+                else x
+                for x in arrays
+            ]
+        else:
+            # dtype check to exclude e.g. range objects, scalars
+            arrays = [x.copy() if hasattr(x, "dtype") else x for x in arrays]
+
+    return arrays_to_mgr(arrays, columns, index, dtype=dtype, typ=typ, consolidate=copy)
+
+
+def nested_data_to_arrays(
+    data: Sequence,
+    columns: Index | None,
+    index: Index | None,
+    dtype: DtypeObj | None,
+) -> tuple[list[ArrayLike], Index, Index]:
+    """
+    Convert a single sequence of arrays to multiple arrays.
+    """
+    # By the time we get here we have already checked treat_as_nested(data)
+
+    if is_named_tuple(data[0]) and columns is None:
+        columns = ensure_index(data[0]._fields)
+
+    arrays, columns = to_arrays(data, columns, dtype=dtype)
+    columns = ensure_index(columns)
+
+    if index is None:
+        if isinstance(data[0], ABCSeries):
+            index = _get_names_from_index(data)
+        else:
+            index = default_index(len(data))
+
+    return arrays, columns, index
+
+
+def treat_as_nested(data) -> bool:
+    """
+    Check if we should use nested_data_to_arrays.
+    """
+    return (
+        len(data) > 0
+        and is_list_like(data[0])
+        and getattr(data[0], "ndim", 1) == 1
+        and not (isinstance(data, ExtensionArray) and data.ndim == 2)
+    )
+
+
+# ---------------------------------------------------------------------
+
+
+def _prep_ndarraylike(values, copy: bool = True) -> np.ndarray:
+    # values is specifically _not_ ndarray, EA, Index, or Series
+    # We only get here with `not treat_as_nested(values)`
+
+    if len(values) == 0:
+        # TODO: check for length-zero range, in which case return int64 dtype?
+        # TODO: reuse anything in try_cast?
+        return np.empty((0, 0), dtype=object)
+    elif isinstance(values, range):
+        arr = range_to_ndarray(values)
+        return arr[..., np.newaxis]
+
+    def convert(v):
+        if not is_list_like(v) or isinstance(v, ABCDataFrame):
+            return v
+
+        v = extract_array(v, extract_numpy=True)
+        res = maybe_convert_platform(v)
+        # We don't do maybe_infer_to_datetimelike here bc we will end up doing
+        #  it column-by-column in ndarray_to_mgr
+        return res
+
+    # we could have a 1-dim or 2-dim list here
+    # this is equiv of np.asarray, but does object conversion
+    # and platform dtype preservation
+    # does not convert e.g. [1, "a", True] to ["1", "a", "True"] like
+    #  np.asarray would
+    if is_list_like(values[0]):
+        values = np.array([convert(v) for v in values])
+    elif isinstance(values[0], np.ndarray) and values[0].ndim == 0:
+        # GH#21861 see test_constructor_list_of_lists
+        values = np.array([convert(v) for v in values])
+    else:
+        values = convert(values)
+
+    return _ensure_2d(values)
+
+
+def _ensure_2d(values: np.ndarray) -> np.ndarray:
+    """
+    Reshape 1D values, raise on anything else other than 2D.
+    """
+    if values.ndim == 1:
+        values = values.reshape((values.shape[0], 1))
+    elif values.ndim != 2:
+        raise ValueError(f"Must pass 2-d input. shape={values.shape}")
+    return values
+
+
+def _homogenize(
+    data, index: Index, dtype: DtypeObj | None
+) -> tuple[list[ArrayLike], list[Any]]:
+    oindex = None
+    homogenized = []
+    # if the original array-like in `data` is a Series, keep track of this Series' refs
+    refs: list[Any] = []
+
+    for val in data:
+        if isinstance(val, (ABCSeries, Index)):
+            if dtype is not None:
+                val = val.astype(dtype, copy=False)
+            if isinstance(val, ABCSeries) and val.index is not index:
+                # Forces alignment. No need to copy data since we
+                # are putting it into an ndarray later
+                val = val.reindex(index, copy=False)
+            refs.append(val._references)
+            val = val._values
+        else:
+            if isinstance(val, dict):
+                # GH#41785 this _should_ be equivalent to (but faster than)
+                #  val = Series(val, index=index)._values
+                if oindex is None:
+                    oindex = index.astype("O")
+
+                if isinstance(index, (DatetimeIndex, TimedeltaIndex)):
+                    # see test_constructor_dict_datetime64_index
+                    val = dict_compat(val)
+                else:
+                    # see test_constructor_subclass_dict
+                    val = dict(val)
+                val = lib.fast_multiget(val, oindex._values, default=np.nan)
+
+            val = sanitize_array(val, index, dtype=dtype, copy=False)
+            com.require_length_match(val, index)
+            refs.append(None)
+
+        homogenized.append(val)
+
+    return homogenized, refs
+
+
+def _extract_index(data) -> Index:
+    """
+    Try to infer an Index from the passed data, raise ValueError on failure.
+    """
+    index: Index
+    if len(data) == 0:
+        return default_index(0)
+
+    raw_lengths = []
+    indexes: list[list[Hashable] | Index] = []
+
+    have_raw_arrays = False
+    have_series = False
+    have_dicts = False
+
+    for val in data:
+        if isinstance(val, ABCSeries):
+            have_series = True
+            indexes.append(val.index)
+        elif isinstance(val, dict):
+            have_dicts = True
+            indexes.append(list(val.keys()))
+        elif is_list_like(val) and getattr(val, "ndim", 1) == 1:
+            have_raw_arrays = True
+            raw_lengths.append(len(val))
+        elif isinstance(val, np.ndarray) and val.ndim > 1:
+            raise ValueError("Per-column arrays must each be 1-dimensional")
+
+    if not indexes and not raw_lengths:
+        raise ValueError("If using all scalar values, you must pass an index")
+
+    if have_series:
+        index = union_indexes(indexes)
+    elif have_dicts:
+        index = union_indexes(indexes, sort=False)
+
+    if have_raw_arrays:
+        lengths = list(set(raw_lengths))
+        if len(lengths) > 1:
+            raise ValueError("All arrays must be of the same length")
+
+        if have_dicts:
+            raise ValueError(
+                "Mixing dicts with non-Series may lead to ambiguous ordering."
+            )
+
+        if have_series:
+            if lengths[0] != len(index):
+                msg = (
+                    f"array length {lengths[0]} does not match index "
+                    f"length {len(index)}"
+                )
+                raise ValueError(msg)
+        else:
+            index = default_index(lengths[0])
+
+    return ensure_index(index)
+
+
+def reorder_arrays(
+    arrays: list[ArrayLike], arr_columns: Index, columns: Index | None, length: int
+) -> tuple[list[ArrayLike], Index]:
+    """
+    Pre-emptively (cheaply) reindex arrays with new columns.
+    """
+    # reorder according to the columns
+    if columns is not None:
+        if not columns.equals(arr_columns):
+            # if they are equal, there is nothing to do
+            new_arrays: list[ArrayLike] = []
+            indexer = arr_columns.get_indexer(columns)
+            for i, k in enumerate(indexer):
+                if k == -1:
+                    # by convention default is all-NaN object dtype
+                    arr = np.empty(length, dtype=object)
+                    arr.fill(np.nan)
+                else:
+                    arr = arrays[k]
+                new_arrays.append(arr)
+
+            arrays = new_arrays
+            arr_columns = columns
+
+    return arrays, arr_columns
+
+
+def _get_names_from_index(data) -> Index:
+    has_some_name = any(getattr(s, "name", None) is not None for s in data)
+    if not has_some_name:
+        return default_index(len(data))
+
+    index: list[Hashable] = list(range(len(data)))
+    count = 0
+    for i, s in enumerate(data):
+        n = getattr(s, "name", None)
+        if n is not None:
+            index[i] = n
+        else:
+            index[i] = f"Unnamed {count}"
+            count += 1
+
+    return Index(index)
+
+
+def _get_axes(
+    N: int, K: int, index: Index | None, columns: Index | None
+) -> tuple[Index, Index]:
+    # helper to create the axes as indexes
+    # return axes or defaults
+
+    if index is None:
+        index = default_index(N)
+    else:
+        index = ensure_index(index)
+
+    if columns is None:
+        columns = default_index(K)
+    else:
+        columns = ensure_index(columns)
+    return index, columns
+
+
+def dataclasses_to_dicts(data):
+    """
+    Converts a list of dataclass instances to a list of dictionaries.
+
+    Parameters
+    ----------
+    data : List[Type[dataclass]]
+
+    Returns
+    --------
+    list_dict : List[dict]
+
+    Examples
+    --------
+    >>> from dataclasses import dataclass
+    >>> @dataclass
+    ... class Point:
+    ...     x: int
+    ...     y: int
+
+    >>> dataclasses_to_dicts([Point(1, 2), Point(2, 3)])
+    [{'x': 1, 'y': 2}, {'x': 2, 'y': 3}]
+
+    """
+    from dataclasses import asdict
+
+    return list(map(asdict, data))
+
+
+# ---------------------------------------------------------------------
+# Conversion of Inputs to Arrays
+
+
+def to_arrays(
+    data, columns: Index | None, dtype: DtypeObj | None = None
+) -> tuple[list[ArrayLike], Index]:
+    """
+    Return list of arrays, columns.
+
+    Returns
+    -------
+    list[ArrayLike]
+        These will become columns in a DataFrame.
+    Index
+        This will become frame.columns.
+
+    Notes
+    -----
+    Ensures that len(result_arrays) == len(result_index).
+    """
+
+    if not len(data):
+        if isinstance(data, np.ndarray):
+            if data.dtype.names is not None:
+                # i.e. numpy structured array
+                columns = ensure_index(data.dtype.names)
+                arrays = [data[name] for name in columns]
+
+                if len(data) == 0:
+                    # GH#42456 the indexing above results in list of 2D ndarrays
+                    # TODO: is that an issue with numpy?
+                    for i, arr in enumerate(arrays):
+                        if arr.ndim == 2:
+                            arrays[i] = arr[:, 0]
+
+                return arrays, columns
+        return [], ensure_index([])
+
+    elif isinstance(data, np.ndarray) and data.dtype.names is not None:
+        # e.g. recarray
+        columns = Index(list(data.dtype.names))
+        arrays = [data[k] for k in columns]
+        return arrays, columns
+
+    if isinstance(data[0], (list, tuple)):
+        arr = _list_to_arrays(data)
+    elif isinstance(data[0], abc.Mapping):
+        arr, columns = _list_of_dict_to_arrays(data, columns)
+    elif isinstance(data[0], ABCSeries):
+        arr, columns = _list_of_series_to_arrays(data, columns)
+    else:
+        # last ditch effort
+        data = [tuple(x) for x in data]
+        arr = _list_to_arrays(data)
+
+    content, columns = _finalize_columns_and_data(arr, columns, dtype)
+    return content, columns
+
+
+def _list_to_arrays(data: list[tuple | list]) -> np.ndarray:
+    # Returned np.ndarray has ndim = 2
+    # Note: we already check len(data) > 0 before getting hre
+    if isinstance(data[0], tuple):
+        content = lib.to_object_array_tuples(data)
+    else:
+        # list of lists
+        content = lib.to_object_array(data)
+    return content
+
+
+def _list_of_series_to_arrays(
+    data: list,
+    columns: Index | None,
+) -> tuple[np.ndarray, Index]:
+    # returned np.ndarray has ndim == 2
+
+    if columns is None:
+        # We know pass_data is non-empty because data[0] is a Series
+        pass_data = [x for x in data if isinstance(x, (ABCSeries, ABCDataFrame))]
+        columns = get_objs_combined_axis(pass_data, sort=False)
+
+    indexer_cache: dict[int, np.ndarray] = {}
+
+    aligned_values = []
+    for s in data:
+        index = getattr(s, "index", None)
+        if index is None:
+            index = default_index(len(s))
+
+        if id(index) in indexer_cache:
+            indexer = indexer_cache[id(index)]
+        else:
+            indexer = indexer_cache[id(index)] = index.get_indexer(columns)
+
+        values = extract_array(s, extract_numpy=True)
+        aligned_values.append(algorithms.take_nd(values, indexer))
+
+    content = np.vstack(aligned_values)
+    return content, columns
+
+
+def _list_of_dict_to_arrays(
+    data: list[dict],
+    columns: Index | None,
+) -> tuple[np.ndarray, Index]:
+    """
+    Convert list of dicts to numpy arrays
+
+    if `columns` is not passed, column names are inferred from the records
+    - for OrderedDict and dicts, the column names match
+      the key insertion-order from the first record to the last.
+    - For other kinds of dict-likes, the keys are lexically sorted.
+
+    Parameters
+    ----------
+    data : iterable
+        collection of records (OrderedDict, dict)
+    columns: iterables or None
+
+    Returns
+    -------
+    content : np.ndarray[object, ndim=2]
+    columns : Index
+    """
+    if columns is None:
+        gen = (list(x.keys()) for x in data)
+        sort = not any(isinstance(d, dict) for d in data)
+        pre_cols = lib.fast_unique_multiple_list_gen(gen, sort=sort)
+        columns = ensure_index(pre_cols)
+
+    # assure that they are of the base dict class and not of derived
+    # classes
+    data = [d if type(d) is dict else dict(d) for d in data]  # noqa: E721
+
+    content = lib.dicts_to_array(data, list(columns))
+    return content, columns
+
+
+def _finalize_columns_and_data(
+    content: np.ndarray,  # ndim == 2
+    columns: Index | None,
+    dtype: DtypeObj | None,
+) -> tuple[list[ArrayLike], Index]:
+    """
+    Ensure we have valid columns, cast object dtypes if possible.
+    """
+    contents = list(content.T)
+
+    try:
+        columns = _validate_or_indexify_columns(contents, columns)
+    except AssertionError as err:
+        # GH#26429 do not raise user-facing AssertionError
+        raise ValueError(err) from err
+
+    if len(contents) and contents[0].dtype == np.object_:
+        contents = convert_object_array(contents, dtype=dtype)
+
+    return contents, columns
+
+
+def _validate_or_indexify_columns(
+    content: list[np.ndarray], columns: Index | None
+) -> Index:
+    """
+    If columns is None, make numbers as column names; Otherwise, validate that
+    columns have valid length.
+
+    Parameters
+    ----------
+    content : list of np.ndarrays
+    columns : Index or None
+
+    Returns
+    -------
+    Index
+        If columns is None, assign positional column index value as columns.
+
+    Raises
+    ------
+    1. AssertionError when content is not composed of list of lists, and if
+        length of columns is not equal to length of content.
+    2. ValueError when content is list of lists, but length of each sub-list
+        is not equal
+    3. ValueError when content is list of lists, but length of sub-list is
+        not equal to length of content
+    """
+    if columns is None:
+        columns = default_index(len(content))
+    else:
+        # Add mask for data which is composed of list of lists
+        is_mi_list = isinstance(columns, list) and all(
+            isinstance(col, list) for col in columns
+        )
+
+        if not is_mi_list and len(columns) != len(content):  # pragma: no cover
+            # caller's responsibility to check for this...
+            raise AssertionError(
+                f"{len(columns)} columns passed, passed data had "
+                f"{len(content)} columns"
+            )
+        if is_mi_list:
+            # check if nested list column, length of each sub-list should be equal
+            if len({len(col) for col in columns}) > 1:
+                raise ValueError(
+                    "Length of columns passed for MultiIndex columns is different"
+                )
+
+            # if columns is not empty and length of sublist is not equal to content
+            if columns and len(columns[0]) != len(content):
+                raise ValueError(
+                    f"{len(columns[0])} columns passed, passed data had "
+                    f"{len(content)} columns"
+                )
+    return columns
+
+
+def convert_object_array(
+    content: list[npt.NDArray[np.object_]],
+    dtype: DtypeObj | None,
+    dtype_backend: str = "numpy",
+    coerce_float: bool = False,
+) -> list[ArrayLike]:
+    """
+    Internal function to convert object array.
+
+    Parameters
+    ----------
+    content: List[np.ndarray]
+    dtype: np.dtype or ExtensionDtype
+    dtype_backend: Controls if nullable/pyarrow dtypes are returned.
+    coerce_float: Cast floats that are integers to int.
+
+    Returns
+    -------
+    List[ArrayLike]
+    """
+    # provide soft conversion of object dtypes
+
+    def convert(arr):
+        if dtype != np.dtype("O"):
+            arr = lib.maybe_convert_objects(
+                arr,
+                try_float=coerce_float,
+                convert_to_nullable_dtype=dtype_backend != "numpy",
+            )
+            # Notes on cases that get here 2023-02-15
+            # 1) we DO get here when arr is all Timestamps and dtype=None
+            # 2) disabling this doesn't break the world, so this must be
+            #    getting caught at a higher level
+            # 3) passing convert_non_numeric to maybe_convert_objects get this right
+            # 4) convert_non_numeric?
+
+            if dtype is None:
+                if arr.dtype == np.dtype("O"):
+                    # i.e. maybe_convert_objects didn't convert
+                    arr = maybe_infer_to_datetimelike(arr)
+                    if dtype_backend != "numpy" and arr.dtype == np.dtype("O"):
+                        new_dtype = StringDtype()
+                        arr_cls = new_dtype.construct_array_type()
+                        arr = arr_cls._from_sequence(arr, dtype=new_dtype)
+                elif dtype_backend != "numpy" and isinstance(arr, np.ndarray):
+                    if arr.dtype.kind in "iufb":
+                        arr = pd_array(arr, copy=False)
+
+            elif isinstance(dtype, ExtensionDtype):
+                # TODO: test(s) that get here
+                # TODO: try to de-duplicate this convert function with
+                #  core.construction functions
+                cls = dtype.construct_array_type()
+                arr = cls._from_sequence(arr, dtype=dtype, copy=False)
+            elif dtype.kind in "mM":
+                # This restriction is harmless bc these are the only cases
+                #  where maybe_cast_to_datetime is not a no-op.
+                # Here we know:
+                #  1) dtype.kind in "mM" and
+                #  2) arr is either object or numeric dtype
+                arr = maybe_cast_to_datetime(arr, dtype)
+
+        return arr
+
+    arrays = [convert(arr) for arr in content]
+
+    return arrays

venv/lib/python3.10/site-packages/pandas/core/internals/managers.py

@@ -0,0 +1,2375 @@
+from __future__ import annotations
+
+from collections.abc import (
+    Hashable,
+    Sequence,
+)
+import itertools
+from typing import (
+    TYPE_CHECKING,
+    Callable,
+    Literal,
+    cast,
+)
+import warnings
+
+import numpy as np
+
+from pandas._config import (
+    using_copy_on_write,
+    warn_copy_on_write,
+)
+
+from pandas._libs import (
+    internals as libinternals,
+    lib,
+)
+from pandas._libs.internals import (
+    BlockPlacement,
+    BlockValuesRefs,
+)
+from pandas._libs.tslibs import Timestamp
+from pandas.errors import PerformanceWarning
+from pandas.util._decorators import cache_readonly
+from pandas.util._exceptions import find_stack_level
+
+from pandas.core.dtypes.cast import infer_dtype_from_scalar
+from pandas.core.dtypes.common import (
+    ensure_platform_int,
+    is_1d_only_ea_dtype,
+    is_list_like,
+)
+from pandas.core.dtypes.dtypes import (
+    DatetimeTZDtype,
+    ExtensionDtype,
+)
+from pandas.core.dtypes.generic import (
+    ABCDataFrame,
+    ABCSeries,
+)
+from pandas.core.dtypes.missing import (
+    array_equals,
+    isna,
+)
+
+import pandas.core.algorithms as algos
+from pandas.core.arrays import (
+    ArrowExtensionArray,
+    ArrowStringArray,
+    DatetimeArray,
+)
+from pandas.core.arrays._mixins import NDArrayBackedExtensionArray
+from pandas.core.construction import (
+    ensure_wrapped_if_datetimelike,
+    extract_array,
+)
+from pandas.core.indexers import maybe_convert_indices
+from pandas.core.indexes.api import (
+    Index,
+    ensure_index,
+)
+from pandas.core.internals.base import (
+    DataManager,
+    SingleDataManager,
+    ensure_np_dtype,
+    interleaved_dtype,
+)
+from pandas.core.internals.blocks import (
+    COW_WARNING_GENERAL_MSG,
+    COW_WARNING_SETITEM_MSG,
+    Block,
+    NumpyBlock,
+    ensure_block_shape,
+    extend_blocks,
+    get_block_type,
+    maybe_coerce_values,
+    new_block,
+    new_block_2d,
+)
+from pandas.core.internals.ops import (
+    blockwise_all,
+    operate_blockwise,
+)
+
+if TYPE_CHECKING:
+    from pandas._typing import (
+        ArrayLike,
+        AxisInt,
+        DtypeObj,
+        QuantileInterpolation,
+        Self,
+        Shape,
+        npt,
+    )
+
+    from pandas.api.extensions import ExtensionArray
+
+
+class BaseBlockManager(DataManager):
+    """
+    Core internal data structure to implement DataFrame, Series, etc.
+
+    Manage a bunch of labeled 2D mixed-type ndarrays. Essentially it's a
+    lightweight blocked set of labeled data to be manipulated by the DataFrame
+    public API class
+
+    Attributes
+    ----------
+    shape
+    ndim
+    axes
+    values
+    items
+
+    Methods
+    -------
+    set_axis(axis, new_labels)
+    copy(deep=True)
+
+    get_dtypes
+
+    apply(func, axes, block_filter_fn)
+
+    get_bool_data
+    get_numeric_data
+
+    get_slice(slice_like, axis)
+    get(label)
+    iget(loc)
+
+    take(indexer, axis)
+    reindex_axis(new_labels, axis)
+    reindex_indexer(new_labels, indexer, axis)
+
+    delete(label)
+    insert(loc, label, value)
+    set(label, value)
+
+    Parameters
+    ----------
+    blocks: Sequence of Block
+    axes: Sequence of Index
+    verify_integrity: bool, default True
+
+    Notes
+    -----
+    This is *not* a public API class
+    """
+
+    __slots__ = ()
+
+    _blknos: npt.NDArray[np.intp]
+    _blklocs: npt.NDArray[np.intp]
+    blocks: tuple[Block, ...]
+    axes: list[Index]
+
+    @property
+    def ndim(self) -> int:
+        raise NotImplementedError
+
+    _known_consolidated: bool
+    _is_consolidated: bool
+
+    def __init__(self, blocks, axes, verify_integrity: bool = True) -> None:
+        raise NotImplementedError
+
+    @classmethod
+    def from_blocks(cls, blocks: list[Block], axes: list[Index]) -> Self:
+        raise NotImplementedError
+
+    @property
+    def blknos(self) -> npt.NDArray[np.intp]:
+        """
+        Suppose we want to find the array corresponding to our i'th column.
+
+        blknos[i] identifies the block from self.blocks that contains this column.
+
+        blklocs[i] identifies the column of interest within
+        self.blocks[self.blknos[i]]
+        """
+        if self._blknos is None:
+            # Note: these can be altered by other BlockManager methods.
+            self._rebuild_blknos_and_blklocs()
+
+        return self._blknos
+
+    @property
+    def blklocs(self) -> npt.NDArray[np.intp]:
+        """
+        See blknos.__doc__
+        """
+        if self._blklocs is None:
+            # Note: these can be altered by other BlockManager methods.
+            self._rebuild_blknos_and_blklocs()
+
+        return self._blklocs
+
+    def make_empty(self, axes=None) -> Self:
+        """return an empty BlockManager with the items axis of len 0"""
+        if axes is None:
+            axes = [Index([])] + self.axes[1:]
+
+        # preserve dtype if possible
+        if self.ndim == 1:
+            assert isinstance(self, SingleBlockManager)  # for mypy
+            blk = self.blocks[0]
+            arr = blk.values[:0]
+            bp = BlockPlacement(slice(0, 0))
+            nb = blk.make_block_same_class(arr, placement=bp)
+            blocks = [nb]
+        else:
+            blocks = []
+        return type(self).from_blocks(blocks, axes)
+
+    def __nonzero__(self) -> bool:
+        return True
+
+    # Python3 compat
+    __bool__ = __nonzero__
+
+    def _normalize_axis(self, axis: AxisInt) -> int:
+        # switch axis to follow BlockManager logic
+        if self.ndim == 2:
+            axis = 1 if axis == 0 else 0
+        return axis
+
+    def set_axis(self, axis: AxisInt, new_labels: Index) -> None:
+        # Caller is responsible for ensuring we have an Index object.
+        self._validate_set_axis(axis, new_labels)
+        self.axes[axis] = new_labels
+
+    @property
+    def is_single_block(self) -> bool:
+        # Assumes we are 2D; overridden by SingleBlockManager
+        return len(self.blocks) == 1
+
+    @property
+    def items(self) -> Index:
+        return self.axes[0]
+
+    def _has_no_reference(self, i: int) -> bool:
+        """
+        Check for column `i` if it has references.
+        (whether it references another array or is itself being referenced)
+        Returns True if the column has no references.
+        """
+        blkno = self.blknos[i]
+        return self._has_no_reference_block(blkno)
+
+    def _has_no_reference_block(self, blkno: int) -> bool:
+        """
+        Check for block `i` if it has references.
+        (whether it references another array or is itself being referenced)
+        Returns True if the block has no references.
+        """
+        return not self.blocks[blkno].refs.has_reference()
+
+    def add_references(self, mgr: BaseBlockManager) -> None:
+        """
+        Adds the references from one manager to another. We assume that both
+        managers have the same block structure.
+        """
+        if len(self.blocks) != len(mgr.blocks):
+            # If block structure changes, then we made a copy
+            return
+        for i, blk in enumerate(self.blocks):
+            blk.refs = mgr.blocks[i].refs
+            blk.refs.add_reference(blk)
+
+    def references_same_values(self, mgr: BaseBlockManager, blkno: int) -> bool:
+        """
+        Checks if two blocks from two different block managers reference the
+        same underlying values.
+        """
+        blk = self.blocks[blkno]
+        return any(blk is ref() for ref in mgr.blocks[blkno].refs.referenced_blocks)
+
+    def get_dtypes(self) -> npt.NDArray[np.object_]:
+        dtypes = np.array([blk.dtype for blk in self.blocks], dtype=object)
+        return dtypes.take(self.blknos)
+
+    @property
+    def arrays(self) -> list[ArrayLike]:
+        """
+        Quick access to the backing arrays of the Blocks.
+
+        Only for compatibility with ArrayManager for testing convenience.
+        Not to be used in actual code, and return value is not the same as the
+        ArrayManager method (list of 1D arrays vs iterator of 2D ndarrays / 1D EAs).
+
+        Warning! The returned arrays don't handle Copy-on-Write, so this should
+        be used with caution (only in read-mode).
+        """
+        return [blk.values for blk in self.blocks]
+
+    def __repr__(self) -> str:
+        output = type(self).__name__
+        for i, ax in enumerate(self.axes):
+            if i == 0:
+                output += f"\nItems: {ax}"
+            else:
+                output += f"\nAxis {i}: {ax}"
+
+        for block in self.blocks:
+            output += f"\n{block}"
+        return output
+
+    def apply(
+        self,
+        f,
+        align_keys: list[str] | None = None,
+        **kwargs,
+    ) -> Self:
+        """
+        Iterate over the blocks, collect and create a new BlockManager.
+
+        Parameters
+        ----------
+        f : str or callable
+            Name of the Block method to apply.
+        align_keys: List[str] or None, default None
+        **kwargs
+            Keywords to pass to `f`
+
+        Returns
+        -------
+        BlockManager
+        """
+        assert "filter" not in kwargs
+
+        align_keys = align_keys or []
+        result_blocks: list[Block] = []
+        # fillna: Series/DataFrame is responsible for making sure value is aligned
+
+        aligned_args = {k: kwargs[k] for k in align_keys}
+
+        for b in self.blocks:
+            if aligned_args:
+                for k, obj in aligned_args.items():
+                    if isinstance(obj, (ABCSeries, ABCDataFrame)):
+                        # The caller is responsible for ensuring that
+                        #  obj.axes[-1].equals(self.items)
+                        if obj.ndim == 1:
+                            kwargs[k] = obj.iloc[b.mgr_locs.indexer]._values
+                        else:
+                            kwargs[k] = obj.iloc[:, b.mgr_locs.indexer]._values
+                    else:
+                        # otherwise we have an ndarray
+                        kwargs[k] = obj[b.mgr_locs.indexer]
+
+            if callable(f):
+                applied = b.apply(f, **kwargs)
+            else:
+                applied = getattr(b, f)(**kwargs)
+            result_blocks = extend_blocks(applied, result_blocks)
+
+        out = type(self).from_blocks(result_blocks, self.axes)
+        return out
+
+    # Alias so we can share code with ArrayManager
+    apply_with_block = apply
+
+    def setitem(self, indexer, value, warn: bool = True) -> Self:
+        """
+        Set values with indexer.
+
+        For SingleBlockManager, this backs s[indexer] = value
+        """
+        if isinstance(indexer, np.ndarray) and indexer.ndim > self.ndim:
+            raise ValueError(f"Cannot set values with ndim > {self.ndim}")
+
+        if warn and warn_copy_on_write() and not self._has_no_reference(0):
+            warnings.warn(
+                COW_WARNING_GENERAL_MSG,
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
+
+        elif using_copy_on_write() and not self._has_no_reference(0):
+            # this method is only called if there is a single block -> hardcoded 0
+            # Split blocks to only copy the columns we want to modify
+            if self.ndim == 2 and isinstance(indexer, tuple):
+                blk_loc = self.blklocs[indexer[1]]
+                if is_list_like(blk_loc) and blk_loc.ndim == 2:
+                    blk_loc = np.squeeze(blk_loc, axis=0)
+                elif not is_list_like(blk_loc):
+                    # Keep dimension and copy data later
+                    blk_loc = [blk_loc]  # type: ignore[assignment]
+                if len(blk_loc) == 0:
+                    return self.copy(deep=False)
+
+                values = self.blocks[0].values
+                if values.ndim == 2:
+                    values = values[blk_loc]
+                    # "T" has no attribute "_iset_split_block"
+                    self._iset_split_block(  # type: ignore[attr-defined]
+                        0, blk_loc, values
+                    )
+                    # first block equals values
+                    self.blocks[0].setitem((indexer[0], np.arange(len(blk_loc))), value)
+                    return self
+            # No need to split if we either set all columns or on a single block
+            # manager
+            self = self.copy()
+
+        return self.apply("setitem", indexer=indexer, value=value)
+
+    def diff(self, n: int) -> Self:
+        # only reached with self.ndim == 2
+        return self.apply("diff", n=n)
+
+    def astype(self, dtype, copy: bool | None = False, errors: str = "raise") -> Self:
+        if copy is None:
+            if using_copy_on_write():
+                copy = False
+            else:
+                copy = True
+        elif using_copy_on_write():
+            copy = False
+
+        return self.apply(
+            "astype",
+            dtype=dtype,
+            copy=copy,
+            errors=errors,
+            using_cow=using_copy_on_write(),
+        )
+
+    def convert(self, copy: bool | None) -> Self:
+        if copy is None:
+            if using_copy_on_write():
+                copy = False
+            else:
+                copy = True
+        elif using_copy_on_write():
+            copy = False
+
+        return self.apply("convert", copy=copy, using_cow=using_copy_on_write())
+
+    def convert_dtypes(self, **kwargs):
+        if using_copy_on_write():
+            copy = False
+        else:
+            copy = True
+
+        return self.apply(
+            "convert_dtypes", copy=copy, using_cow=using_copy_on_write(), **kwargs
+        )
+
+    def get_values_for_csv(
+        self, *, float_format, date_format, decimal, na_rep: str = "nan", quoting=None
+    ) -> Self:
+        """
+        Convert values to native types (strings / python objects) that are used
+        in formatting (repr / csv).
+        """
+        return self.apply(
+            "get_values_for_csv",
+            na_rep=na_rep,
+            quoting=quoting,
+            float_format=float_format,
+            date_format=date_format,
+            decimal=decimal,
+        )
+
+    @property
+    def any_extension_types(self) -> bool:
+        """Whether any of the blocks in this manager are extension blocks"""
+        return any(block.is_extension for block in self.blocks)
+
+    @property
+    def is_view(self) -> bool:
+        """return a boolean if we are a single block and are a view"""
+        if len(self.blocks) == 1:
+            return self.blocks[0].is_view
+
+        # It is technically possible to figure out which blocks are views
+        # e.g. [ b.values.base is not None for b in self.blocks ]
+        # but then we have the case of possibly some blocks being a view
+        # and some blocks not. setting in theory is possible on the non-view
+        # blocks w/o causing a SettingWithCopy raise/warn. But this is a bit
+        # complicated
+
+        return False
+
+    def _get_data_subset(self, predicate: Callable) -> Self:
+        blocks = [blk for blk in self.blocks if predicate(blk.values)]
+        return self._combine(blocks)
+
+    def get_bool_data(self) -> Self:
+        """
+        Select blocks that are bool-dtype and columns from object-dtype blocks
+        that are all-bool.
+        """
+
+        new_blocks = []
+
+        for blk in self.blocks:
+            if blk.dtype == bool:
+                new_blocks.append(blk)
+
+            elif blk.is_object:
+                nbs = blk._split()
+                new_blocks.extend(nb for nb in nbs if nb.is_bool)
+
+        return self._combine(new_blocks)
+
+    def get_numeric_data(self) -> Self:
+        numeric_blocks = [blk for blk in self.blocks if blk.is_numeric]
+        if len(numeric_blocks) == len(self.blocks):
+            # Avoid somewhat expensive _combine
+            return self
+        return self._combine(numeric_blocks)
+
+    def _combine(self, blocks: list[Block], index: Index | None = None) -> Self:
+        """return a new manager with the blocks"""
+        if len(blocks) == 0:
+            if self.ndim == 2:
+                # retain our own Index dtype
+                if index is not None:
+                    axes = [self.items[:0], index]
+                else:
+                    axes = [self.items[:0]] + self.axes[1:]
+                return self.make_empty(axes)
+            return self.make_empty()
+
+        # FIXME: optimization potential
+        indexer = np.sort(np.concatenate([b.mgr_locs.as_array for b in blocks]))
+        inv_indexer = lib.get_reverse_indexer(indexer, self.shape[0])
+
+        new_blocks: list[Block] = []
+        for b in blocks:
+            nb = b.copy(deep=False)
+            nb.mgr_locs = BlockPlacement(inv_indexer[nb.mgr_locs.indexer])
+            new_blocks.append(nb)
+
+        axes = list(self.axes)
+        if index is not None:
+            axes[-1] = index
+        axes[0] = self.items.take(indexer)
+
+        return type(self).from_blocks(new_blocks, axes)
+
+    @property
+    def nblocks(self) -> int:
+        return len(self.blocks)
+
+    def copy(self, deep: bool | None | Literal["all"] = True) -> Self:
+        """
+        Make deep or shallow copy of BlockManager
+
+        Parameters
+        ----------
+        deep : bool, string or None, default True
+            If False or None, return a shallow copy (do not copy data)
+            If 'all', copy data and a deep copy of the index
+
+        Returns
+        -------
+        BlockManager
+        """
+        if deep is None:
+            if using_copy_on_write():
+                # use shallow copy
+                deep = False
+            else:
+                # preserve deep copy for BlockManager with copy=None
+                deep = True
+
+        # this preserves the notion of view copying of axes
+        if deep:
+            # hit in e.g. tests.io.json.test_pandas
+
+            def copy_func(ax):
+                return ax.copy(deep=True) if deep == "all" else ax.view()
+
+            new_axes = [copy_func(ax) for ax in self.axes]
+        else:
+            if using_copy_on_write():
+                new_axes = [ax.view() for ax in self.axes]
+            else:
+                new_axes = list(self.axes)
+
+        res = self.apply("copy", deep=deep)
+        res.axes = new_axes
+
+        if self.ndim > 1:
+            # Avoid needing to re-compute these
+            blknos = self._blknos
+            if blknos is not None:
+                res._blknos = blknos.copy()
+                res._blklocs = self._blklocs.copy()
+
+        if deep:
+            res._consolidate_inplace()
+        return res
+
+    def consolidate(self) -> Self:
+        """
+        Join together blocks having same dtype
+
+        Returns
+        -------
+        y : BlockManager
+        """
+        if self.is_consolidated():
+            return self
+
+        bm = type(self)(self.blocks, self.axes, verify_integrity=False)
+        bm._is_consolidated = False
+        bm._consolidate_inplace()
+        return bm
+
+    def reindex_indexer(
+        self,
+        new_axis: Index,
+        indexer: npt.NDArray[np.intp] | None,
+        axis: AxisInt,
+        fill_value=None,
+        allow_dups: bool = False,
+        copy: bool | None = True,
+        only_slice: bool = False,
+        *,
+        use_na_proxy: bool = False,
+    ) -> Self:
+        """
+        Parameters
+        ----------
+        new_axis : Index
+        indexer : ndarray[intp] or None
+        axis : int
+        fill_value : object, default None
+        allow_dups : bool, default False
+        copy : bool or None, default True
+            If None, regard as False to get shallow copy.
+        only_slice : bool, default False
+            Whether to take views, not copies, along columns.
+        use_na_proxy : bool, default False
+            Whether to use a np.void ndarray for newly introduced columns.
+
+        pandas-indexer with -1's only.
+        """
+        if copy is None:
+            if using_copy_on_write():
+                # use shallow copy
+                copy = False
+            else:
+                # preserve deep copy for BlockManager with copy=None
+                copy = True
+
+        if indexer is None:
+            if new_axis is self.axes[axis] and not copy:
+                return self
+
+            result = self.copy(deep=copy)
+            result.axes = list(self.axes)
+            result.axes[axis] = new_axis
+            return result
+
+        # Should be intp, but in some cases we get int64 on 32bit builds
+        assert isinstance(indexer, np.ndarray)
+
+        # some axes don't allow reindexing with dups
+        if not allow_dups:
+            self.axes[axis]._validate_can_reindex(indexer)
+
+        if axis >= self.ndim:
+            raise IndexError("Requested axis not found in manager")
+
+        if axis == 0:
+            new_blocks = self._slice_take_blocks_ax0(
+                indexer,
+                fill_value=fill_value,
+                only_slice=only_slice,
+                use_na_proxy=use_na_proxy,
+            )
+        else:
+            new_blocks = [
+                blk.take_nd(
+                    indexer,
+                    axis=1,
+                    fill_value=(
+                        fill_value if fill_value is not None else blk.fill_value
+                    ),
+                )
+                for blk in self.blocks
+            ]
+
+        new_axes = list(self.axes)
+        new_axes[axis] = new_axis
+
+        new_mgr = type(self).from_blocks(new_blocks, new_axes)
+        if axis == 1:
+            # We can avoid the need to rebuild these
+            new_mgr._blknos = self.blknos.copy()
+            new_mgr._blklocs = self.blklocs.copy()
+        return new_mgr
+
+    def _slice_take_blocks_ax0(
+        self,
+        slice_or_indexer: slice | np.ndarray,
+        fill_value=lib.no_default,
+        only_slice: bool = False,
+        *,
+        use_na_proxy: bool = False,
+        ref_inplace_op: bool = False,
+    ) -> list[Block]:
+        """
+        Slice/take blocks along axis=0.
+
+        Overloaded for SingleBlock
+
+        Parameters
+        ----------
+        slice_or_indexer : slice or np.ndarray[int64]
+        fill_value : scalar, default lib.no_default
+        only_slice : bool, default False
+            If True, we always return views on existing arrays, never copies.
+            This is used when called from ops.blockwise.operate_blockwise.
+        use_na_proxy : bool, default False
+            Whether to use a np.void ndarray for newly introduced columns.
+        ref_inplace_op: bool, default False
+            Don't track refs if True because we operate inplace
+
+        Returns
+        -------
+        new_blocks : list of Block
+        """
+        allow_fill = fill_value is not lib.no_default
+
+        sl_type, slobj, sllen = _preprocess_slice_or_indexer(
+            slice_or_indexer, self.shape[0], allow_fill=allow_fill
+        )
+
+        if self.is_single_block:
+            blk = self.blocks[0]
+
+            if sl_type == "slice":
+                # GH#32959 EABlock would fail since we can't make 0-width
+                # TODO(EA2D): special casing unnecessary with 2D EAs
+                if sllen == 0:
+                    return []
+                bp = BlockPlacement(slice(0, sllen))
+                return [blk.getitem_block_columns(slobj, new_mgr_locs=bp)]
+            elif not allow_fill or self.ndim == 1:
+                if allow_fill and fill_value is None:
+                    fill_value = blk.fill_value
+
+                if not allow_fill and only_slice:
+                    # GH#33597 slice instead of take, so we get
+                    #  views instead of copies
+                    blocks = [
+                        blk.getitem_block_columns(
+                            slice(ml, ml + 1),
+                            new_mgr_locs=BlockPlacement(i),
+                            ref_inplace_op=ref_inplace_op,
+                        )
+                        for i, ml in enumerate(slobj)
+                    ]
+                    return blocks
+                else:
+                    bp = BlockPlacement(slice(0, sllen))
+                    return [
+                        blk.take_nd(
+                            slobj,
+                            axis=0,
+                            new_mgr_locs=bp,
+                            fill_value=fill_value,
+                        )
+                    ]
+
+        if sl_type == "slice":
+            blknos = self.blknos[slobj]
+            blklocs = self.blklocs[slobj]
+        else:
+            blknos = algos.take_nd(
+                self.blknos, slobj, fill_value=-1, allow_fill=allow_fill
+            )
+            blklocs = algos.take_nd(
+                self.blklocs, slobj, fill_value=-1, allow_fill=allow_fill
+            )
+
+        # When filling blknos, make sure blknos is updated before appending to
+        # blocks list, that way new blkno is exactly len(blocks).
+        blocks = []
+        group = not only_slice
+        for blkno, mgr_locs in libinternals.get_blkno_placements(blknos, group=group):
+            if blkno == -1:
+                # If we've got here, fill_value was not lib.no_default
+
+                blocks.append(
+                    self._make_na_block(
+                        placement=mgr_locs,
+                        fill_value=fill_value,
+                        use_na_proxy=use_na_proxy,
+                    )
+                )
+            else:
+                blk = self.blocks[blkno]
+
+                # Otherwise, slicing along items axis is necessary.
+                if not blk._can_consolidate and not blk._validate_ndim:
+                    # i.e. we dont go through here for DatetimeTZBlock
+                    # A non-consolidatable block, it's easy, because there's
+                    # only one item and each mgr loc is a copy of that single
+                    # item.
+                    deep = not (only_slice or using_copy_on_write())
+                    for mgr_loc in mgr_locs:
+                        newblk = blk.copy(deep=deep)
+                        newblk.mgr_locs = BlockPlacement(slice(mgr_loc, mgr_loc + 1))
+                        blocks.append(newblk)
+
+                else:
+                    # GH#32779 to avoid the performance penalty of copying,
+                    #  we may try to only slice
+                    taker = blklocs[mgr_locs.indexer]
+                    max_len = max(len(mgr_locs), taker.max() + 1)
+                    if only_slice or using_copy_on_write():
+                        taker = lib.maybe_indices_to_slice(taker, max_len)
+
+                    if isinstance(taker, slice):
+                        nb = blk.getitem_block_columns(taker, new_mgr_locs=mgr_locs)
+                        blocks.append(nb)
+                    elif only_slice:
+                        # GH#33597 slice instead of take, so we get
+                        #  views instead of copies
+                        for i, ml in zip(taker, mgr_locs):
+                            slc = slice(i, i + 1)
+                            bp = BlockPlacement(ml)
+                            nb = blk.getitem_block_columns(slc, new_mgr_locs=bp)
+                            # We have np.shares_memory(nb.values, blk.values)
+                            blocks.append(nb)
+                    else:
+                        nb = blk.take_nd(taker, axis=0, new_mgr_locs=mgr_locs)
+                        blocks.append(nb)
+
+        return blocks
+
+    def _make_na_block(
+        self, placement: BlockPlacement, fill_value=None, use_na_proxy: bool = False
+    ) -> Block:
+        # Note: we only get here with self.ndim == 2
+
+        if use_na_proxy:
+            assert fill_value is None
+            shape = (len(placement), self.shape[1])
+            vals = np.empty(shape, dtype=np.void)
+            nb = NumpyBlock(vals, placement, ndim=2)
+            return nb
+
+        if fill_value is None:
+            fill_value = np.nan
+
+        shape = (len(placement), self.shape[1])
+
+        dtype, fill_value = infer_dtype_from_scalar(fill_value)
+        block_values = make_na_array(dtype, shape, fill_value)
+        return new_block_2d(block_values, placement=placement)
+
+    def take(
+        self,
+        indexer: npt.NDArray[np.intp],
+        axis: AxisInt = 1,
+        verify: bool = True,
+    ) -> Self:
+        """
+        Take items along any axis.
+
+        indexer : np.ndarray[np.intp]
+        axis : int, default 1
+        verify : bool, default True
+            Check that all entries are between 0 and len(self) - 1, inclusive.
+            Pass verify=False if this check has been done by the caller.
+
+        Returns
+        -------
+        BlockManager
+        """
+        # Caller is responsible for ensuring indexer annotation is accurate
+
+        n = self.shape[axis]
+        indexer = maybe_convert_indices(indexer, n, verify=verify)
+
+        new_labels = self.axes[axis].take(indexer)
+        return self.reindex_indexer(
+            new_axis=new_labels,
+            indexer=indexer,
+            axis=axis,
+            allow_dups=True,
+            copy=None,
+        )
+
+
+class BlockManager(libinternals.BlockManager, BaseBlockManager):
+    """
+    BaseBlockManager that holds 2D blocks.
+    """
+
+    ndim = 2
+
+    # ----------------------------------------------------------------
+    # Constructors
+
+    def __init__(
+        self,
+        blocks: Sequence[Block],
+        axes: Sequence[Index],
+        verify_integrity: bool = True,
+    ) -> None:
+        if verify_integrity:
+            # Assertion disabled for performance
+            # assert all(isinstance(x, Index) for x in axes)
+
+            for block in blocks:
+                if self.ndim != block.ndim:
+                    raise AssertionError(
+                        f"Number of Block dimensions ({block.ndim}) must equal "
+                        f"number of axes ({self.ndim})"
+                    )
+                # As of 2.0, the caller is responsible for ensuring that
+                #  DatetimeTZBlock with block.ndim == 2 has block.values.ndim ==2;
+                #  previously there was a special check for fastparquet compat.
+
+            self._verify_integrity()
+
+    def _verify_integrity(self) -> None:
+        mgr_shape = self.shape
+        tot_items = sum(len(x.mgr_locs) for x in self.blocks)
+        for block in self.blocks:
+            if block.shape[1:] != mgr_shape[1:]:
+                raise_construction_error(tot_items, block.shape[1:], self.axes)
+        if len(self.items) != tot_items:
+            raise AssertionError(
+                "Number of manager items must equal union of "
+                f"block items\n# manager items: {len(self.items)}, # "
+                f"tot_items: {tot_items}"
+            )
+
+    @classmethod
+    def from_blocks(cls, blocks: list[Block], axes: list[Index]) -> Self:
+        """
+        Constructor for BlockManager and SingleBlockManager with same signature.
+        """
+        return cls(blocks, axes, verify_integrity=False)
+
+    # ----------------------------------------------------------------
+    # Indexing
+
+    def fast_xs(self, loc: int) -> SingleBlockManager:
+        """
+        Return the array corresponding to `frame.iloc[loc]`.
+
+        Parameters
+        ----------
+        loc : int
+
+        Returns
+        -------
+        np.ndarray or ExtensionArray
+        """
+        if len(self.blocks) == 1:
+            # TODO: this could be wrong if blk.mgr_locs is not slice(None)-like;
+            #  is this ruled out in the general case?
+            result = self.blocks[0].iget((slice(None), loc))
+            # in the case of a single block, the new block is a view
+            bp = BlockPlacement(slice(0, len(result)))
+            block = new_block(
+                result,
+                placement=bp,
+                ndim=1,
+                refs=self.blocks[0].refs,
+            )
+            return SingleBlockManager(block, self.axes[0])
+
+        dtype = interleaved_dtype([blk.dtype for blk in self.blocks])
+
+        n = len(self)
+
+        if isinstance(dtype, ExtensionDtype):
+            # TODO: use object dtype as workaround for non-performant
+            #  EA.__setitem__ methods. (primarily ArrowExtensionArray.__setitem__
+            #  when iteratively setting individual values)
+            #  https://github.com/pandas-dev/pandas/pull/54508#issuecomment-1675827918
+            result = np.empty(n, dtype=object)
+        else:
+            result = np.empty(n, dtype=dtype)
+            result = ensure_wrapped_if_datetimelike(result)
+
+        for blk in self.blocks:
+            # Such assignment may incorrectly coerce NaT to None
+            # result[blk.mgr_locs] = blk._slice((slice(None), loc))
+            for i, rl in enumerate(blk.mgr_locs):
+                result[rl] = blk.iget((i, loc))
+
+        if isinstance(dtype, ExtensionDtype):
+            cls = dtype.construct_array_type()
+            result = cls._from_sequence(result, dtype=dtype)
+
+        bp = BlockPlacement(slice(0, len(result)))
+        block = new_block(result, placement=bp, ndim=1)
+        return SingleBlockManager(block, self.axes[0])
+
+    def iget(self, i: int, track_ref: bool = True) -> SingleBlockManager:
+        """
+        Return the data as a SingleBlockManager.
+        """
+        block = self.blocks[self.blknos[i]]
+        values = block.iget(self.blklocs[i])
+
+        # shortcut for select a single-dim from a 2-dim BM
+        bp = BlockPlacement(slice(0, len(values)))
+        nb = type(block)(
+            values, placement=bp, ndim=1, refs=block.refs if track_ref else None
+        )
+        return SingleBlockManager(nb, self.axes[1])
+
+    def iget_values(self, i: int) -> ArrayLike:
+        """
+        Return the data for column i as the values (ndarray or ExtensionArray).
+
+        Warning! The returned array is a view but doesn't handle Copy-on-Write,
+        so this should be used with caution.
+        """
+        # TODO(CoW) making the arrays read-only might make this safer to use?
+        block = self.blocks[self.blknos[i]]
+        values = block.iget(self.blklocs[i])
+        return values
+
+    @property
+    def column_arrays(self) -> list[np.ndarray]:
+        """
+        Used in the JSON C code to access column arrays.
+        This optimizes compared to using `iget_values` by converting each
+
+        Warning! This doesn't handle Copy-on-Write, so should be used with
+        caution (current use case of consuming this in the JSON code is fine).
+        """
+        # This is an optimized equivalent to
+        #  result = [self.iget_values(i) for i in range(len(self.items))]
+        result: list[np.ndarray | None] = [None] * len(self.items)
+
+        for blk in self.blocks:
+            mgr_locs = blk._mgr_locs
+            values = blk.array_values._values_for_json()
+            if values.ndim == 1:
+                # TODO(EA2D): special casing not needed with 2D EAs
+                result[mgr_locs[0]] = values
+
+            else:
+                for i, loc in enumerate(mgr_locs):
+                    result[loc] = values[i]
+
+        # error: Incompatible return value type (got "List[None]",
+        # expected "List[ndarray[Any, Any]]")
+        return result  # type: ignore[return-value]
+
+    def iset(
+        self,
+        loc: int | slice | np.ndarray,
+        value: ArrayLike,
+        inplace: bool = False,
+        refs: BlockValuesRefs | None = None,
+    ) -> None:
+        """
+        Set new item in-place. Does not consolidate. Adds new Block if not
+        contained in the current set of items
+        """
+
+        # FIXME: refactor, clearly separate broadcasting & zip-like assignment
+        #        can prob also fix the various if tests for sparse/categorical
+        if self._blklocs is None and self.ndim > 1:
+            self._rebuild_blknos_and_blklocs()
+
+        # Note: we exclude DTA/TDA here
+        value_is_extension_type = is_1d_only_ea_dtype(value.dtype)
+        if not value_is_extension_type:
+            if value.ndim == 2:
+                value = value.T
+            else:
+                value = ensure_block_shape(value, ndim=2)
+
+            if value.shape[1:] != self.shape[1:]:
+                raise AssertionError(
+                    "Shape of new values must be compatible with manager shape"
+                )
+
+        if lib.is_integer(loc):
+            # We have 6 tests where loc is _not_ an int.
+            # In this case, get_blkno_placements will yield only one tuple,
+            #  containing (self._blknos[loc], BlockPlacement(slice(0, 1, 1)))
+
+            # Check if we can use _iset_single fastpath
+            loc = cast(int, loc)
+            blkno = self.blknos[loc]
+            blk = self.blocks[blkno]
+            if len(blk._mgr_locs) == 1:  # TODO: fastest way to check this?
+                return self._iset_single(
+                    loc,
+                    value,
+                    inplace=inplace,
+                    blkno=blkno,
+                    blk=blk,
+                    refs=refs,
+                )
+
+            # error: Incompatible types in assignment (expression has type
+            # "List[Union[int, slice, ndarray]]", variable has type "Union[int,
+            # slice, ndarray]")
+            loc = [loc]  # type: ignore[assignment]
+
+        # categorical/sparse/datetimetz
+        if value_is_extension_type:
+
+            def value_getitem(placement):
+                return value
+
+        else:
+
+            def value_getitem(placement):
+                return value[placement.indexer]
+
+        # Accessing public blknos ensures the public versions are initialized
+        blknos = self.blknos[loc]
+        blklocs = self.blklocs[loc].copy()
+
+        unfit_mgr_locs = []
+        unfit_val_locs = []
+        removed_blknos = []
+        for blkno_l, val_locs in libinternals.get_blkno_placements(blknos, group=True):
+            blk = self.blocks[blkno_l]
+            blk_locs = blklocs[val_locs.indexer]
+            if inplace and blk.should_store(value):
+                # Updating inplace -> check if we need to do Copy-on-Write
+                if using_copy_on_write() and not self._has_no_reference_block(blkno_l):
+                    self._iset_split_block(
+                        blkno_l, blk_locs, value_getitem(val_locs), refs=refs
+                    )
+                else:
+                    blk.set_inplace(blk_locs, value_getitem(val_locs))
+                    continue
+            else:
+                unfit_mgr_locs.append(blk.mgr_locs.as_array[blk_locs])
+                unfit_val_locs.append(val_locs)
+
+                # If all block items are unfit, schedule the block for removal.
+                if len(val_locs) == len(blk.mgr_locs):
+                    removed_blknos.append(blkno_l)
+                    continue
+                else:
+                    # Defer setting the new values to enable consolidation
+                    self._iset_split_block(blkno_l, blk_locs, refs=refs)
+
+        if len(removed_blknos):
+            # Remove blocks & update blknos accordingly
+            is_deleted = np.zeros(self.nblocks, dtype=np.bool_)
+            is_deleted[removed_blknos] = True
+
+            new_blknos = np.empty(self.nblocks, dtype=np.intp)
+            new_blknos.fill(-1)
+            new_blknos[~is_deleted] = np.arange(self.nblocks - len(removed_blknos))
+            self._blknos = new_blknos[self._blknos]
+            self.blocks = tuple(
+                blk for i, blk in enumerate(self.blocks) if i not in set(removed_blknos)
+            )
+
+        if unfit_val_locs:
+            unfit_idxr = np.concatenate(unfit_mgr_locs)
+            unfit_count = len(unfit_idxr)
+
+            new_blocks: list[Block] = []
+            if value_is_extension_type:
+                # This code (ab-)uses the fact that EA blocks contain only
+                # one item.
+                # TODO(EA2D): special casing unnecessary with 2D EAs
+                new_blocks.extend(
+                    new_block_2d(
+                        values=value,
+                        placement=BlockPlacement(slice(mgr_loc, mgr_loc + 1)),
+                        refs=refs,
+                    )
+                    for mgr_loc in unfit_idxr
+                )
+
+                self._blknos[unfit_idxr] = np.arange(unfit_count) + len(self.blocks)
+                self._blklocs[unfit_idxr] = 0
+
+            else:
+                # unfit_val_locs contains BlockPlacement objects
+                unfit_val_items = unfit_val_locs[0].append(unfit_val_locs[1:])
+
+                new_blocks.append(
+                    new_block_2d(
+                        values=value_getitem(unfit_val_items),
+                        placement=BlockPlacement(unfit_idxr),
+                        refs=refs,
+                    )
+                )
+
+                self._blknos[unfit_idxr] = len(self.blocks)
+                self._blklocs[unfit_idxr] = np.arange(unfit_count)
+
+            self.blocks += tuple(new_blocks)
+
+            # Newly created block's dtype may already be present.
+            self._known_consolidated = False
+
+    def _iset_split_block(
+        self,
+        blkno_l: int,
+        blk_locs: np.ndarray | list[int],
+        value: ArrayLike | None = None,
+        refs: BlockValuesRefs | None = None,
+    ) -> None:
+        """Removes columns from a block by splitting the block.
+
+        Avoids copying the whole block through slicing and updates the manager
+        after determinint the new block structure. Optionally adds a new block,
+        otherwise has to be done by the caller.
+
+        Parameters
+        ----------
+        blkno_l: The block number to operate on, relevant for updating the manager
+        blk_locs: The locations of our block that should be deleted.
+        value: The value to set as a replacement.
+        refs: The reference tracking object of the value to set.
+        """
+        blk = self.blocks[blkno_l]
+
+        if self._blklocs is None:
+            self._rebuild_blknos_and_blklocs()
+
+        nbs_tup = tuple(blk.delete(blk_locs))
+        if value is not None:
+            locs = blk.mgr_locs.as_array[blk_locs]
+            first_nb = new_block_2d(value, BlockPlacement(locs), refs=refs)
+        else:
+            first_nb = nbs_tup[0]
+            nbs_tup = tuple(nbs_tup[1:])
+
+        nr_blocks = len(self.blocks)
+        blocks_tup = (
+            self.blocks[:blkno_l] + (first_nb,) + self.blocks[blkno_l + 1 :] + nbs_tup
+        )
+        self.blocks = blocks_tup
+
+        if not nbs_tup and value is not None:
+            # No need to update anything if split did not happen
+            return
+
+        self._blklocs[first_nb.mgr_locs.indexer] = np.arange(len(first_nb))
+
+        for i, nb in enumerate(nbs_tup):
+            self._blklocs[nb.mgr_locs.indexer] = np.arange(len(nb))
+            self._blknos[nb.mgr_locs.indexer] = i + nr_blocks
+
+    def _iset_single(
+        self,
+        loc: int,
+        value: ArrayLike,
+        inplace: bool,
+        blkno: int,
+        blk: Block,
+        refs: BlockValuesRefs | None = None,
+    ) -> None:
+        """
+        Fastpath for iset when we are only setting a single position and
+        the Block currently in that position is itself single-column.
+
+        In this case we can swap out the entire Block and blklocs and blknos
+        are unaffected.
+        """
+        # Caller is responsible for verifying value.shape
+
+        if inplace and blk.should_store(value):
+            copy = False
+            if using_copy_on_write() and not self._has_no_reference_block(blkno):
+                # perform Copy-on-Write and clear the reference
+                copy = True
+            iloc = self.blklocs[loc]
+            blk.set_inplace(slice(iloc, iloc + 1), value, copy=copy)
+            return
+
+        nb = new_block_2d(value, placement=blk._mgr_locs, refs=refs)
+        old_blocks = self.blocks
+        new_blocks = old_blocks[:blkno] + (nb,) + old_blocks[blkno + 1 :]
+        self.blocks = new_blocks
+        return
+
+    def column_setitem(
+        self, loc: int, idx: int | slice | np.ndarray, value, inplace_only: bool = False
+    ) -> None:
+        """
+        Set values ("setitem") into a single column (not setting the full column).
+
+        This is a method on the BlockManager level, to avoid creating an
+        intermediate Series at the DataFrame level (`s = df[loc]; s[idx] = value`)
+        """
+        needs_to_warn = False
+        if warn_copy_on_write() and not self._has_no_reference(loc):
+            if not isinstance(
+                self.blocks[self.blknos[loc]].values,
+                (ArrowExtensionArray, ArrowStringArray),
+            ):
+                # We might raise if we are in an expansion case, so defer
+                # warning till we actually updated
+                needs_to_warn = True
+
+        elif using_copy_on_write() and not self._has_no_reference(loc):
+            blkno = self.blknos[loc]
+            # Split blocks to only copy the column we want to modify
+            blk_loc = self.blklocs[loc]
+            # Copy our values
+            values = self.blocks[blkno].values
+            if values.ndim == 1:
+                values = values.copy()
+            else:
+                # Use [blk_loc] as indexer to keep ndim=2, this already results in a
+                # copy
+                values = values[[blk_loc]]
+            self._iset_split_block(blkno, [blk_loc], values)
+
+        # this manager is only created temporarily to mutate the values in place
+        # so don't track references, otherwise the `setitem` would perform CoW again
+        col_mgr = self.iget(loc, track_ref=False)
+        if inplace_only:
+            col_mgr.setitem_inplace(idx, value)
+        else:
+            new_mgr = col_mgr.setitem((idx,), value)
+            self.iset(loc, new_mgr._block.values, inplace=True)
+
+        if needs_to_warn:
+            warnings.warn(
+                COW_WARNING_GENERAL_MSG,
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
+
+    def insert(self, loc: int, item: Hashable, value: ArrayLike, refs=None) -> None:
+        """
+        Insert item at selected position.
+
+        Parameters
+        ----------
+        loc : int
+        item : hashable
+        value : np.ndarray or ExtensionArray
+        refs : The reference tracking object of the value to set.
+        """
+        with warnings.catch_warnings():
+            # TODO: re-issue this with setitem-specific message?
+            warnings.filterwarnings(
+                "ignore",
+                "The behavior of Index.insert with object-dtype is deprecated",
+                category=FutureWarning,
+            )
+            new_axis = self.items.insert(loc, item)
+
+        if value.ndim == 2:
+            value = value.T
+            if len(value) > 1:
+                raise ValueError(
+                    f"Expected a 1D array, got an array with shape {value.T.shape}"
+                )
+        else:
+            value = ensure_block_shape(value, ndim=self.ndim)
+
+        bp = BlockPlacement(slice(loc, loc + 1))
+        block = new_block_2d(values=value, placement=bp, refs=refs)
+
+        if not len(self.blocks):
+            # Fastpath
+            self._blklocs = np.array([0], dtype=np.intp)
+            self._blknos = np.array([0], dtype=np.intp)
+        else:
+            self._insert_update_mgr_locs(loc)
+            self._insert_update_blklocs_and_blknos(loc)
+
+        self.axes[0] = new_axis
+        self.blocks += (block,)
+
+        self._known_consolidated = False
+
+        if sum(not block.is_extension for block in self.blocks) > 100:
+            warnings.warn(
+                "DataFrame is highly fragmented.  This is usually the result "
+                "of calling `frame.insert` many times, which has poor performance.  "
+                "Consider joining all columns at once using pd.concat(axis=1) "
+                "instead. To get a de-fragmented frame, use `newframe = frame.copy()`",
+                PerformanceWarning,
+                stacklevel=find_stack_level(),
+            )
+
+    def _insert_update_mgr_locs(self, loc) -> None:
+        """
+        When inserting a new Block at location 'loc', we increment
+        all of the mgr_locs of blocks above that by one.
+        """
+        for blkno, count in _fast_count_smallints(self.blknos[loc:]):
+            # .620 this way, .326 of which is in increment_above
+            blk = self.blocks[blkno]
+            blk._mgr_locs = blk._mgr_locs.increment_above(loc)
+
+    def _insert_update_blklocs_and_blknos(self, loc) -> None:
+        """
+        When inserting a new Block at location 'loc', we update our
+        _blklocs and _blknos.
+        """
+
+        # Accessing public blklocs ensures the public versions are initialized
+        if loc == self.blklocs.shape[0]:
+            # np.append is a lot faster, let's use it if we can.
+            self._blklocs = np.append(self._blklocs, 0)
+            self._blknos = np.append(self._blknos, len(self.blocks))
+        elif loc == 0:
+            # np.append is a lot faster, let's use it if we can.
+            self._blklocs = np.append(self._blklocs[::-1], 0)[::-1]
+            self._blknos = np.append(self._blknos[::-1], len(self.blocks))[::-1]
+        else:
+            new_blklocs, new_blknos = libinternals.update_blklocs_and_blknos(
+                self.blklocs, self.blknos, loc, len(self.blocks)
+            )
+            self._blklocs = new_blklocs
+            self._blknos = new_blknos
+
+    def idelete(self, indexer) -> BlockManager:
+        """
+        Delete selected locations, returning a new BlockManager.
+        """
+        is_deleted = np.zeros(self.shape[0], dtype=np.bool_)
+        is_deleted[indexer] = True
+        taker = (~is_deleted).nonzero()[0]
+
+        nbs = self._slice_take_blocks_ax0(taker, only_slice=True, ref_inplace_op=True)
+        new_columns = self.items[~is_deleted]
+        axes = [new_columns, self.axes[1]]
+        return type(self)(tuple(nbs), axes, verify_integrity=False)
+
+    # ----------------------------------------------------------------
+    # Block-wise Operation
+
+    def grouped_reduce(self, func: Callable) -> Self:
+        """
+        Apply grouped reduction function blockwise, returning a new BlockManager.
+
+        Parameters
+        ----------
+        func : grouped reduction function
+
+        Returns
+        -------
+        BlockManager
+        """
+        result_blocks: list[Block] = []
+
+        for blk in self.blocks:
+            if blk.is_object:
+                # split on object-dtype blocks bc some columns may raise
+                #  while others do not.
+                for sb in blk._split():
+                    applied = sb.apply(func)
+                    result_blocks = extend_blocks(applied, result_blocks)
+            else:
+                applied = blk.apply(func)
+                result_blocks = extend_blocks(applied, result_blocks)
+
+        if len(result_blocks) == 0:
+            nrows = 0
+        else:
+            nrows = result_blocks[0].values.shape[-1]
+        index = Index(range(nrows))
+
+        return type(self).from_blocks(result_blocks, [self.axes[0], index])
+
+    def reduce(self, func: Callable) -> Self:
+        """
+        Apply reduction function blockwise, returning a single-row BlockManager.
+
+        Parameters
+        ----------
+        func : reduction function
+
+        Returns
+        -------
+        BlockManager
+        """
+        # If 2D, we assume that we're operating column-wise
+        assert self.ndim == 2
+
+        res_blocks: list[Block] = []
+        for blk in self.blocks:
+            nbs = blk.reduce(func)
+            res_blocks.extend(nbs)
+
+        index = Index([None])  # placeholder
+        new_mgr = type(self).from_blocks(res_blocks, [self.items, index])
+        return new_mgr
+
+    def operate_blockwise(self, other: BlockManager, array_op) -> BlockManager:
+        """
+        Apply array_op blockwise with another (aligned) BlockManager.
+        """
+        return operate_blockwise(self, other, array_op)
+
+    def _equal_values(self: BlockManager, other: BlockManager) -> bool:
+        """
+        Used in .equals defined in base class. Only check the column values
+        assuming shape and indexes have already been checked.
+        """
+        return blockwise_all(self, other, array_equals)
+
+    def quantile(
+        self,
+        *,
+        qs: Index,  # with dtype float 64
+        interpolation: QuantileInterpolation = "linear",
+    ) -> Self:
+        """
+        Iterate over blocks applying quantile reduction.
+        This routine is intended for reduction type operations and
+        will do inference on the generated blocks.
+
+        Parameters
+        ----------
+        interpolation : type of interpolation, default 'linear'
+        qs : list of the quantiles to be computed
+
+        Returns
+        -------
+        BlockManager
+        """
+        # Series dispatches to DataFrame for quantile, which allows us to
+        #  simplify some of the code here and in the blocks
+        assert self.ndim >= 2
+        assert is_list_like(qs)  # caller is responsible for this
+
+        new_axes = list(self.axes)
+        new_axes[1] = Index(qs, dtype=np.float64)
+
+        blocks = [
+            blk.quantile(qs=qs, interpolation=interpolation) for blk in self.blocks
+        ]
+
+        return type(self)(blocks, new_axes)
+
+    # ----------------------------------------------------------------
+
+    def unstack(self, unstacker, fill_value) -> BlockManager:
+        """
+        Return a BlockManager with all blocks unstacked.
+
+        Parameters
+        ----------
+        unstacker : reshape._Unstacker
+        fill_value : Any
+            fill_value for newly introduced missing values.
+
+        Returns
+        -------
+        unstacked : BlockManager
+        """
+        new_columns = unstacker.get_new_columns(self.items)
+        new_index = unstacker.new_index
+
+        allow_fill = not unstacker.mask_all
+        if allow_fill:
+            # calculating the full mask once and passing it to Block._unstack is
+            #  faster than letting calculating it in each repeated call
+            new_mask2D = (~unstacker.mask).reshape(*unstacker.full_shape)
+            needs_masking = new_mask2D.any(axis=0)
+        else:
+            needs_masking = np.zeros(unstacker.full_shape[1], dtype=bool)
+
+        new_blocks: list[Block] = []
+        columns_mask: list[np.ndarray] = []
+
+        if len(self.items) == 0:
+            factor = 1
+        else:
+            fac = len(new_columns) / len(self.items)
+            assert fac == int(fac)
+            factor = int(fac)
+
+        for blk in self.blocks:
+            mgr_locs = blk.mgr_locs
+            new_placement = mgr_locs.tile_for_unstack(factor)
+
+            blocks, mask = blk._unstack(
+                unstacker,
+                fill_value,
+                new_placement=new_placement,
+                needs_masking=needs_masking,
+            )
+
+            new_blocks.extend(blocks)
+            columns_mask.extend(mask)
+
+            # Block._unstack should ensure this holds,
+            assert mask.sum() == sum(len(nb._mgr_locs) for nb in blocks)
+            # In turn this ensures that in the BlockManager call below
+            #  we have len(new_columns) == sum(x.shape[0] for x in new_blocks)
+            #  which suffices to allow us to pass verify_inegrity=False
+
+        new_columns = new_columns[columns_mask]
+
+        bm = BlockManager(new_blocks, [new_columns, new_index], verify_integrity=False)
+        return bm
+
+    def to_dict(self) -> dict[str, Self]:
+        """
+        Return a dict of str(dtype) -> BlockManager
+
+        Returns
+        -------
+        values : a dict of dtype -> BlockManager
+        """
+
+        bd: dict[str, list[Block]] = {}
+        for b in self.blocks:
+            bd.setdefault(str(b.dtype), []).append(b)
+
+        # TODO(EA2D): the combine will be unnecessary with 2D EAs
+        return {dtype: self._combine(blocks) for dtype, blocks in bd.items()}
+
+    def as_array(
+        self,
+        dtype: np.dtype | None = None,
+        copy: bool = False,
+        na_value: object = lib.no_default,
+    ) -> np.ndarray:
+        """
+        Convert the blockmanager data into an numpy array.
+
+        Parameters
+        ----------
+        dtype : np.dtype or None, default None
+            Data type of the return array.
+        copy : bool, default False
+            If True then guarantee that a copy is returned. A value of
+            False does not guarantee that the underlying data is not
+            copied.
+        na_value : object, default lib.no_default
+            Value to be used as the missing value sentinel.
+
+        Returns
+        -------
+        arr : ndarray
+        """
+        passed_nan = lib.is_float(na_value) and isna(na_value)
+
+        if len(self.blocks) == 0:
+            arr = np.empty(self.shape, dtype=float)
+            return arr.transpose()
+
+        if self.is_single_block:
+            blk = self.blocks[0]
+
+            if na_value is not lib.no_default:
+                # We want to copy when na_value is provided to avoid
+                # mutating the original object
+                if lib.is_np_dtype(blk.dtype, "f") and passed_nan:
+                    # We are already numpy-float and na_value=np.nan
+                    pass
+                else:
+                    copy = True
+
+            if blk.is_extension:
+                # Avoid implicit conversion of extension blocks to object
+
+                # error: Item "ndarray" of "Union[ndarray, ExtensionArray]" has no
+                # attribute "to_numpy"
+                arr = blk.values.to_numpy(  # type: ignore[union-attr]
+                    dtype=dtype,
+                    na_value=na_value,
+                    copy=copy,
+                ).reshape(blk.shape)
+            elif not copy:
+                arr = np.asarray(blk.values, dtype=dtype)
+            else:
+                arr = np.array(blk.values, dtype=dtype, copy=copy)
+
+            if using_copy_on_write() and not copy:
+                arr = arr.view()
+                arr.flags.writeable = False
+        else:
+            arr = self._interleave(dtype=dtype, na_value=na_value)
+            # The underlying data was copied within _interleave, so no need
+            # to further copy if copy=True or setting na_value
+
+        if na_value is lib.no_default:
+            pass
+        elif arr.dtype.kind == "f" and passed_nan:
+            pass
+        else:
+            arr[isna(arr)] = na_value
+
+        return arr.transpose()
+
+    def _interleave(
+        self,
+        dtype: np.dtype | None = None,
+        na_value: object = lib.no_default,
+    ) -> np.ndarray:
+        """
+        Return ndarray from blocks with specified item order
+        Items must be contained in the blocks
+        """
+        if not dtype:
+            # Incompatible types in assignment (expression has type
+            # "Optional[Union[dtype[Any], ExtensionDtype]]", variable has
+            # type "Optional[dtype[Any]]")
+            dtype = interleaved_dtype(  # type: ignore[assignment]
+                [blk.dtype for blk in self.blocks]
+            )
+
+        # error: Argument 1 to "ensure_np_dtype" has incompatible type
+        # "Optional[dtype[Any]]"; expected "Union[dtype[Any], ExtensionDtype]"
+        dtype = ensure_np_dtype(dtype)  # type: ignore[arg-type]
+        result = np.empty(self.shape, dtype=dtype)
+
+        itemmask = np.zeros(self.shape[0])
+
+        if dtype == np.dtype("object") and na_value is lib.no_default:
+            # much more performant than using to_numpy below
+            for blk in self.blocks:
+                rl = blk.mgr_locs
+                arr = blk.get_values(dtype)
+                result[rl.indexer] = arr
+                itemmask[rl.indexer] = 1
+            return result
+
+        for blk in self.blocks:
+            rl = blk.mgr_locs
+            if blk.is_extension:
+                # Avoid implicit conversion of extension blocks to object
+
+                # error: Item "ndarray" of "Union[ndarray, ExtensionArray]" has no
+                # attribute "to_numpy"
+                arr = blk.values.to_numpy(  # type: ignore[union-attr]
+                    dtype=dtype,
+                    na_value=na_value,
+                )
+            else:
+                arr = blk.get_values(dtype)
+            result[rl.indexer] = arr
+            itemmask[rl.indexer] = 1
+
+        if not itemmask.all():
+            raise AssertionError("Some items were not contained in blocks")
+
+        return result
+
+    # ----------------------------------------------------------------
+    # Consolidation
+
+    def is_consolidated(self) -> bool:
+        """
+        Return True if more than one block with the same dtype
+        """
+        if not self._known_consolidated:
+            self._consolidate_check()
+        return self._is_consolidated
+
+    def _consolidate_check(self) -> None:
+        if len(self.blocks) == 1:
+            # fastpath
+            self._is_consolidated = True
+            self._known_consolidated = True
+            return
+        dtypes = [blk.dtype for blk in self.blocks if blk._can_consolidate]
+        self._is_consolidated = len(dtypes) == len(set(dtypes))
+        self._known_consolidated = True
+
+    def _consolidate_inplace(self) -> None:
+        # In general, _consolidate_inplace should only be called via
+        #  DataFrame._consolidate_inplace, otherwise we will fail to invalidate
+        #  the DataFrame's _item_cache. The exception is for newly-created
+        #  BlockManager objects not yet attached to a DataFrame.
+        if not self.is_consolidated():
+            self.blocks = _consolidate(self.blocks)
+            self._is_consolidated = True
+            self._known_consolidated = True
+            self._rebuild_blknos_and_blklocs()
+
+    # ----------------------------------------------------------------
+    # Concatenation
+
+    @classmethod
+    def concat_horizontal(cls, mgrs: list[Self], axes: list[Index]) -> Self:
+        """
+        Concatenate uniformly-indexed BlockManagers horizontally.
+        """
+        offset = 0
+        blocks: list[Block] = []
+        for mgr in mgrs:
+            for blk in mgr.blocks:
+                # We need to do getitem_block here otherwise we would be altering
+                #  blk.mgr_locs in place, which would render it invalid. This is only
+                #  relevant in the copy=False case.
+                nb = blk.slice_block_columns(slice(None))
+                nb._mgr_locs = nb._mgr_locs.add(offset)
+                blocks.append(nb)
+
+            offset += len(mgr.items)
+
+        new_mgr = cls(tuple(blocks), axes)
+        return new_mgr
+
+    @classmethod
+    def concat_vertical(cls, mgrs: list[Self], axes: list[Index]) -> Self:
+        """
+        Concatenate uniformly-indexed BlockManagers vertically.
+        """
+        raise NotImplementedError("This logic lives (for now) in internals.concat")
+
+
+class SingleBlockManager(BaseBlockManager, SingleDataManager):
+    """manage a single block with"""
+
+    @property
+    def ndim(self) -> Literal[1]:
+        return 1
+
+    _is_consolidated = True
+    _known_consolidated = True
+    __slots__ = ()
+    is_single_block = True
+
+    def __init__(
+        self,
+        block: Block,
+        axis: Index,
+        verify_integrity: bool = False,
+    ) -> None:
+        # Assertions disabled for performance
+        # assert isinstance(block, Block), type(block)
+        # assert isinstance(axis, Index), type(axis)
+
+        self.axes = [axis]
+        self.blocks = (block,)
+
+    @classmethod
+    def from_blocks(
+        cls,
+        blocks: list[Block],
+        axes: list[Index],
+    ) -> Self:
+        """
+        Constructor for BlockManager and SingleBlockManager with same signature.
+        """
+        assert len(blocks) == 1
+        assert len(axes) == 1
+        return cls(blocks[0], axes[0], verify_integrity=False)
+
+    @classmethod
+    def from_array(
+        cls, array: ArrayLike, index: Index, refs: BlockValuesRefs | None = None
+    ) -> SingleBlockManager:
+        """
+        Constructor for if we have an array that is not yet a Block.
+        """
+        array = maybe_coerce_values(array)
+        bp = BlockPlacement(slice(0, len(index)))
+        block = new_block(array, placement=bp, ndim=1, refs=refs)
+        return cls(block, index)
+
+    def to_2d_mgr(self, columns: Index) -> BlockManager:
+        """
+        Manager analogue of Series.to_frame
+        """
+        blk = self.blocks[0]
+        arr = ensure_block_shape(blk.values, ndim=2)
+        bp = BlockPlacement(0)
+        new_blk = type(blk)(arr, placement=bp, ndim=2, refs=blk.refs)
+        axes = [columns, self.axes[0]]
+        return BlockManager([new_blk], axes=axes, verify_integrity=False)
+
+    def _has_no_reference(self, i: int = 0) -> bool:
+        """
+        Check for column `i` if it has references.
+        (whether it references another array or is itself being referenced)
+        Returns True if the column has no references.
+        """
+        return not self.blocks[0].refs.has_reference()
+
+    def __getstate__(self):
+        block_values = [b.values for b in self.blocks]
+        block_items = [self.items[b.mgr_locs.indexer] for b in self.blocks]
+        axes_array = list(self.axes)
+
+        extra_state = {
+            "0.14.1": {
+                "axes": axes_array,
+                "blocks": [
+                    {"values": b.values, "mgr_locs": b.mgr_locs.indexer}
+                    for b in self.blocks
+                ],
+            }
+        }
+
+        # First three elements of the state are to maintain forward
+        # compatibility with 0.13.1.
+        return axes_array, block_values, block_items, extra_state
+
+    def __setstate__(self, state) -> None:
+        def unpickle_block(values, mgr_locs, ndim: int) -> Block:
+            # TODO(EA2D): ndim would be unnecessary with 2D EAs
+            # older pickles may store e.g. DatetimeIndex instead of DatetimeArray
+            values = extract_array(values, extract_numpy=True)
+            if not isinstance(mgr_locs, BlockPlacement):
+                mgr_locs = BlockPlacement(mgr_locs)
+
+            values = maybe_coerce_values(values)
+            return new_block(values, placement=mgr_locs, ndim=ndim)
+
+        if isinstance(state, tuple) and len(state) >= 4 and "0.14.1" in state[3]:
+            state = state[3]["0.14.1"]
+            self.axes = [ensure_index(ax) for ax in state["axes"]]
+            ndim = len(self.axes)
+            self.blocks = tuple(
+                unpickle_block(b["values"], b["mgr_locs"], ndim=ndim)
+                for b in state["blocks"]
+            )
+        else:
+            raise NotImplementedError("pre-0.14.1 pickles are no longer supported")
+
+        self._post_setstate()
+
+    def _post_setstate(self) -> None:
+        pass
+
+    @cache_readonly
+    def _block(self) -> Block:
+        return self.blocks[0]
+
+    @property
+    def _blknos(self):
+        """compat with BlockManager"""
+        return None
+
+    @property
+    def _blklocs(self):
+        """compat with BlockManager"""
+        return None
+
+    def get_rows_with_mask(self, indexer: npt.NDArray[np.bool_]) -> Self:
+        # similar to get_slice, but not restricted to slice indexer
+        blk = self._block
+        if using_copy_on_write() and len(indexer) > 0 and indexer.all():
+            return type(self)(blk.copy(deep=False), self.index)
+        array = blk.values[indexer]
+
+        if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "b":
+            # boolean indexing always gives a copy with numpy
+            refs = None
+        else:
+            # TODO(CoW) in theory only need to track reference if new_array is a view
+            refs = blk.refs
+
+        bp = BlockPlacement(slice(0, len(array)))
+        block = type(blk)(array, placement=bp, ndim=1, refs=refs)
+
+        new_idx = self.index[indexer]
+        return type(self)(block, new_idx)
+
+    def get_slice(self, slobj: slice, axis: AxisInt = 0) -> SingleBlockManager:
+        # Assertion disabled for performance
+        # assert isinstance(slobj, slice), type(slobj)
+        if axis >= self.ndim:
+            raise IndexError("Requested axis not found in manager")
+
+        blk = self._block
+        array = blk.values[slobj]
+        bp = BlockPlacement(slice(0, len(array)))
+        # TODO this method is only used in groupby SeriesSplitter at the moment,
+        # so passing refs is not yet covered by the tests
+        block = type(blk)(array, placement=bp, ndim=1, refs=blk.refs)
+        new_index = self.index._getitem_slice(slobj)
+        return type(self)(block, new_index)
+
+    @property
+    def index(self) -> Index:
+        return self.axes[0]
+
+    @property
+    def dtype(self) -> DtypeObj:
+        return self._block.dtype
+
+    def get_dtypes(self) -> npt.NDArray[np.object_]:
+        return np.array([self._block.dtype], dtype=object)
+
+    def external_values(self):
+        """The array that Series.values returns"""
+        return self._block.external_values()
+
+    def internal_values(self):
+        """The array that Series._values returns"""
+        return self._block.values
+
+    def array_values(self) -> ExtensionArray:
+        """The array that Series.array returns"""
+        return self._block.array_values
+
+    def get_numeric_data(self) -> Self:
+        if self._block.is_numeric:
+            return self.copy(deep=False)
+        return self.make_empty()
+
+    @property
+    def _can_hold_na(self) -> bool:
+        return self._block._can_hold_na
+
+    def setitem_inplace(self, indexer, value, warn: bool = True) -> None:
+        """
+        Set values with indexer.
+
+        For Single[Block/Array]Manager, this backs s[indexer] = value
+
+        This is an inplace version of `setitem()`, mutating the manager/values
+        in place, not returning a new Manager (and Block), and thus never changing
+        the dtype.
+        """
+        using_cow = using_copy_on_write()
+        warn_cow = warn_copy_on_write()
+        if (using_cow or warn_cow) and not self._has_no_reference(0):
+            if using_cow:
+                self.blocks = (self._block.copy(),)
+                self._cache.clear()
+            elif warn_cow and warn:
+                warnings.warn(
+                    COW_WARNING_SETITEM_MSG,
+                    FutureWarning,
+                    stacklevel=find_stack_level(),
+                )
+
+        super().setitem_inplace(indexer, value)
+
+    def idelete(self, indexer) -> SingleBlockManager:
+        """
+        Delete single location from SingleBlockManager.
+
+        Ensures that self.blocks doesn't become empty.
+        """
+        nb = self._block.delete(indexer)[0]
+        self.blocks = (nb,)
+        self.axes[0] = self.axes[0].delete(indexer)
+        self._cache.clear()
+        return self
+
+    def fast_xs(self, loc):
+        """
+        fast path for getting a cross-section
+        return a view of the data
+        """
+        raise NotImplementedError("Use series._values[loc] instead")
+
+    def set_values(self, values: ArrayLike) -> None:
+        """
+        Set the values of the single block in place.
+
+        Use at your own risk! This does not check if the passed values are
+        valid for the current Block/SingleBlockManager (length, dtype, etc),
+        and this does not properly keep track of references.
+        """
+        # NOTE(CoW) Currently this is only used for FrameColumnApply.series_generator
+        # which handles CoW by setting the refs manually if necessary
+        self.blocks[0].values = values
+        self.blocks[0]._mgr_locs = BlockPlacement(slice(len(values)))
+
+    def _equal_values(self, other: Self) -> bool:
+        """
+        Used in .equals defined in base class. Only check the column values
+        assuming shape and indexes have already been checked.
+        """
+        # For SingleBlockManager (i.e.Series)
+        if other.ndim != 1:
+            return False
+        left = self.blocks[0].values
+        right = other.blocks[0].values
+        return array_equals(left, right)
+
+
+# --------------------------------------------------------------------
+# Constructor Helpers
+
+
+def create_block_manager_from_blocks(
+    blocks: list[Block],
+    axes: list[Index],
+    consolidate: bool = True,
+    verify_integrity: bool = True,
+) -> BlockManager:
+    # If verify_integrity=False, then caller is responsible for checking
+    #  all(x.shape[-1] == len(axes[1]) for x in blocks)
+    #  sum(x.shape[0] for x in blocks) == len(axes[0])
+    #  set(x for blk in blocks for x in blk.mgr_locs) == set(range(len(axes[0])))
+    #  all(blk.ndim == 2 for blk in blocks)
+    # This allows us to safely pass verify_integrity=False
+
+    try:
+        mgr = BlockManager(blocks, axes, verify_integrity=verify_integrity)
+
+    except ValueError as err:
+        arrays = [blk.values for blk in blocks]
+        tot_items = sum(arr.shape[0] for arr in arrays)
+        raise_construction_error(tot_items, arrays[0].shape[1:], axes, err)
+
+    if consolidate:
+        mgr._consolidate_inplace()
+    return mgr
+
+
+def create_block_manager_from_column_arrays(
+    arrays: list[ArrayLike],
+    axes: list[Index],
+    consolidate: bool,
+    refs: list,
+) -> BlockManager:
+    # Assertions disabled for performance (caller is responsible for verifying)
+    # assert isinstance(axes, list)
+    # assert all(isinstance(x, Index) for x in axes)
+    # assert all(isinstance(x, (np.ndarray, ExtensionArray)) for x in arrays)
+    # assert all(type(x) is not NumpyExtensionArray for x in arrays)
+    # assert all(x.ndim == 1 for x in arrays)
+    # assert all(len(x) == len(axes[1]) for x in arrays)
+    # assert len(arrays) == len(axes[0])
+    # These last three are sufficient to allow us to safely pass
+    #  verify_integrity=False below.
+
+    try:
+        blocks = _form_blocks(arrays, consolidate, refs)
+        mgr = BlockManager(blocks, axes, verify_integrity=False)
+    except ValueError as e:
+        raise_construction_error(len(arrays), arrays[0].shape, axes, e)
+    if consolidate:
+        mgr._consolidate_inplace()
+    return mgr
+
+
+def raise_construction_error(
+    tot_items: int,
+    block_shape: Shape,
+    axes: list[Index],
+    e: ValueError | None = None,
+):
+    """raise a helpful message about our construction"""
+    passed = tuple(map(int, [tot_items] + list(block_shape)))
+    # Correcting the user facing error message during dataframe construction
+    if len(passed) <= 2:
+        passed = passed[::-1]
+
+    implied = tuple(len(ax) for ax in axes)
+    # Correcting the user facing error message during dataframe construction
+    if len(implied) <= 2:
+        implied = implied[::-1]
+
+    # We return the exception object instead of raising it so that we
+    #  can raise it in the caller; mypy plays better with that
+    if passed == implied and e is not None:
+        raise e
+    if block_shape[0] == 0:
+        raise ValueError("Empty data passed with indices specified.")
+    raise ValueError(f"Shape of passed values is {passed}, indices imply {implied}")
+
+
+# -----------------------------------------------------------------------
+
+
+def _grouping_func(tup: tuple[int, ArrayLike]) -> tuple[int, DtypeObj]:
+    dtype = tup[1].dtype
+
+    if is_1d_only_ea_dtype(dtype):
+        # We know these won't be consolidated, so don't need to group these.
+        # This avoids expensive comparisons of CategoricalDtype objects
+        sep = id(dtype)
+    else:
+        sep = 0
+
+    return sep, dtype
+
+
+def _form_blocks(arrays: list[ArrayLike], consolidate: bool, refs: list) -> list[Block]:
+    tuples = list(enumerate(arrays))
+
+    if not consolidate:
+        return _tuples_to_blocks_no_consolidate(tuples, refs)
+
+    # when consolidating, we can ignore refs (either stacking always copies,
+    # or the EA is already copied in the calling dict_to_mgr)
+
+    # group by dtype
+    grouper = itertools.groupby(tuples, _grouping_func)
+
+    nbs: list[Block] = []
+    for (_, dtype), tup_block in grouper:
+        block_type = get_block_type(dtype)
+
+        if isinstance(dtype, np.dtype):
+            is_dtlike = dtype.kind in "mM"
+
+            if issubclass(dtype.type, (str, bytes)):
+                dtype = np.dtype(object)
+
+            values, placement = _stack_arrays(list(tup_block), dtype)
+            if is_dtlike:
+                values = ensure_wrapped_if_datetimelike(values)
+            blk = block_type(values, placement=BlockPlacement(placement), ndim=2)
+            nbs.append(blk)
+
+        elif is_1d_only_ea_dtype(dtype):
+            dtype_blocks = [
+                block_type(x[1], placement=BlockPlacement(x[0]), ndim=2)
+                for x in tup_block
+            ]
+            nbs.extend(dtype_blocks)
+
+        else:
+            dtype_blocks = [
+                block_type(
+                    ensure_block_shape(x[1], 2), placement=BlockPlacement(x[0]), ndim=2
+                )
+                for x in tup_block
+            ]
+            nbs.extend(dtype_blocks)
+    return nbs
+
+
+def _tuples_to_blocks_no_consolidate(tuples, refs) -> list[Block]:
+    # tuples produced within _form_blocks are of the form (placement, array)
+    return [
+        new_block_2d(
+            ensure_block_shape(arr, ndim=2), placement=BlockPlacement(i), refs=ref
+        )
+        for ((i, arr), ref) in zip(tuples, refs)
+    ]
+
+
+def _stack_arrays(tuples, dtype: np.dtype):
+    placement, arrays = zip(*tuples)
+
+    first = arrays[0]
+    shape = (len(arrays),) + first.shape
+
+    stacked = np.empty(shape, dtype=dtype)
+    for i, arr in enumerate(arrays):
+        stacked[i] = arr
+
+    return stacked, placement
+
+
+def _consolidate(blocks: tuple[Block, ...]) -> tuple[Block, ...]:
+    """
+    Merge blocks having same dtype, exclude non-consolidating blocks
+    """
+    # sort by _can_consolidate, dtype
+    gkey = lambda x: x._consolidate_key
+    grouper = itertools.groupby(sorted(blocks, key=gkey), gkey)
+
+    new_blocks: list[Block] = []
+    for (_can_consolidate, dtype), group_blocks in grouper:
+        merged_blocks, _ = _merge_blocks(
+            list(group_blocks), dtype=dtype, can_consolidate=_can_consolidate
+        )
+        new_blocks = extend_blocks(merged_blocks, new_blocks)
+    return tuple(new_blocks)
+
+
+def _merge_blocks(
+    blocks: list[Block], dtype: DtypeObj, can_consolidate: bool
+) -> tuple[list[Block], bool]:
+    if len(blocks) == 1:
+        return blocks, False
+
+    if can_consolidate:
+        # TODO: optimization potential in case all mgrs contain slices and
+        # combination of those slices is a slice, too.
+        new_mgr_locs = np.concatenate([b.mgr_locs.as_array for b in blocks])
+
+        new_values: ArrayLike
+
+        if isinstance(blocks[0].dtype, np.dtype):
+            # error: List comprehension has incompatible type List[Union[ndarray,
+            # ExtensionArray]]; expected List[Union[complex, generic,
+            # Sequence[Union[int, float, complex, str, bytes, generic]],
+            # Sequence[Sequence[Any]], SupportsArray]]
+            new_values = np.vstack([b.values for b in blocks])  # type: ignore[misc]
+        else:
+            bvals = [blk.values for blk in blocks]
+            bvals2 = cast(Sequence[NDArrayBackedExtensionArray], bvals)
+            new_values = bvals2[0]._concat_same_type(bvals2, axis=0)
+
+        argsort = np.argsort(new_mgr_locs)
+        new_values = new_values[argsort]
+        new_mgr_locs = new_mgr_locs[argsort]
+
+        bp = BlockPlacement(new_mgr_locs)
+        return [new_block_2d(new_values, placement=bp)], True
+
+    # can't consolidate --> no merge
+    return blocks, False
+
+
+def _fast_count_smallints(arr: npt.NDArray[np.intp]):
+    """Faster version of set(arr) for sequences of small numbers."""
+    counts = np.bincount(arr)
+    nz = counts.nonzero()[0]
+    # Note: list(zip(...) outperforms list(np.c_[nz, counts[nz]]) here,
+    #  in one benchmark by a factor of 11
+    return zip(nz, counts[nz])
+
+
+def _preprocess_slice_or_indexer(
+    slice_or_indexer: slice | np.ndarray, length: int, allow_fill: bool
+):
+    if isinstance(slice_or_indexer, slice):
+        return (
+            "slice",
+            slice_or_indexer,
+            libinternals.slice_len(slice_or_indexer, length),
+        )
+    else:
+        if (
+            not isinstance(slice_or_indexer, np.ndarray)
+            or slice_or_indexer.dtype.kind != "i"
+        ):
+            dtype = getattr(slice_or_indexer, "dtype", None)
+            raise TypeError(type(slice_or_indexer), dtype)
+
+        indexer = ensure_platform_int(slice_or_indexer)
+        if not allow_fill:
+            indexer = maybe_convert_indices(indexer, length)
+        return "fancy", indexer, len(indexer)
+
+
+def make_na_array(dtype: DtypeObj, shape: Shape, fill_value) -> ArrayLike:
+    if isinstance(dtype, DatetimeTZDtype):
+        # NB: exclude e.g. pyarrow[dt64tz] dtypes
+        ts = Timestamp(fill_value).as_unit(dtype.unit)
+        i8values = np.full(shape, ts._value)
+        dt64values = i8values.view(f"M8[{dtype.unit}]")
+        return DatetimeArray._simple_new(dt64values, dtype=dtype)
+
+    elif is_1d_only_ea_dtype(dtype):
+        dtype = cast(ExtensionDtype, dtype)
+        cls = dtype.construct_array_type()
+
+        missing_arr = cls._from_sequence([], dtype=dtype)
+        ncols, nrows = shape
+        assert ncols == 1, ncols
+        empty_arr = -1 * np.ones((nrows,), dtype=np.intp)
+        return missing_arr.take(empty_arr, allow_fill=True, fill_value=fill_value)
+    elif isinstance(dtype, ExtensionDtype):
+        # TODO: no tests get here, a handful would if we disabled
+        #  the dt64tz special-case above (which is faster)
+        cls = dtype.construct_array_type()
+        missing_arr = cls._empty(shape=shape, dtype=dtype)
+        missing_arr[:] = fill_value
+        return missing_arr
+    else:
+        # NB: we should never get here with dtype integer or bool;
+        #  if we did, the missing_arr.fill would cast to gibberish
+        missing_arr = np.empty(shape, dtype=dtype)
+        missing_arr.fill(fill_value)
+
+        if dtype.kind in "mM":
+            missing_arr = ensure_wrapped_if_datetimelike(missing_arr)
+        return missing_arr

venv/lib/python3.10/site-packages/pandas/core/internals/ops.py

@@ -0,0 +1,154 @@
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    NamedTuple,
+)
+
+from pandas.core.dtypes.common import is_1d_only_ea_dtype
+
+if TYPE_CHECKING:
+    from collections.abc import Iterator
+
+    from pandas._libs.internals import BlockPlacement
+    from pandas._typing import ArrayLike
+
+    from pandas.core.internals.blocks import Block
+    from pandas.core.internals.managers import BlockManager
+
+
+class BlockPairInfo(NamedTuple):
+    lvals: ArrayLike
+    rvals: ArrayLike
+    locs: BlockPlacement
+    left_ea: bool
+    right_ea: bool
+    rblk: Block
+
+
+def _iter_block_pairs(
+    left: BlockManager, right: BlockManager
+) -> Iterator[BlockPairInfo]:
+    # At this point we have already checked the parent DataFrames for
+    #  assert rframe._indexed_same(lframe)
+
+    for blk in left.blocks:
+        locs = blk.mgr_locs
+        blk_vals = blk.values
+
+        left_ea = blk_vals.ndim == 1
+
+        rblks = right._slice_take_blocks_ax0(locs.indexer, only_slice=True)
+
+        # Assertions are disabled for performance, but should hold:
+        # if left_ea:
+        #    assert len(locs) == 1, locs
+        #    assert len(rblks) == 1, rblks
+        #    assert rblks[0].shape[0] == 1, rblks[0].shape
+
+        for rblk in rblks:
+            right_ea = rblk.values.ndim == 1
+
+            lvals, rvals = _get_same_shape_values(blk, rblk, left_ea, right_ea)
+            info = BlockPairInfo(lvals, rvals, locs, left_ea, right_ea, rblk)
+            yield info
+
+
+def operate_blockwise(
+    left: BlockManager, right: BlockManager, array_op
+) -> BlockManager:
+    # At this point we have already checked the parent DataFrames for
+    #  assert rframe._indexed_same(lframe)
+
+    res_blks: list[Block] = []
+    for lvals, rvals, locs, left_ea, right_ea, rblk in _iter_block_pairs(left, right):
+        res_values = array_op(lvals, rvals)
+        if (
+            left_ea
+            and not right_ea
+            and hasattr(res_values, "reshape")
+            and not is_1d_only_ea_dtype(res_values.dtype)
+        ):
+            res_values = res_values.reshape(1, -1)
+        nbs = rblk._split_op_result(res_values)
+
+        # Assertions are disabled for performance, but should hold:
+        # if right_ea or left_ea:
+        #    assert len(nbs) == 1
+        # else:
+        #    assert res_values.shape == lvals.shape, (res_values.shape, lvals.shape)
+
+        _reset_block_mgr_locs(nbs, locs)
+
+        res_blks.extend(nbs)
+
+    # Assertions are disabled for performance, but should hold:
+    #  slocs = {y for nb in res_blks for y in nb.mgr_locs.as_array}
+    #  nlocs = sum(len(nb.mgr_locs.as_array) for nb in res_blks)
+    #  assert nlocs == len(left.items), (nlocs, len(left.items))
+    #  assert len(slocs) == nlocs, (len(slocs), nlocs)
+    #  assert slocs == set(range(nlocs)), slocs
+
+    new_mgr = type(right)(tuple(res_blks), axes=right.axes, verify_integrity=False)
+    return new_mgr
+
+
+def _reset_block_mgr_locs(nbs: list[Block], locs) -> None:
+    """
+    Reset mgr_locs to correspond to our original DataFrame.
+    """
+    for nb in nbs:
+        nblocs = locs[nb.mgr_locs.indexer]
+        nb.mgr_locs = nblocs
+        # Assertions are disabled for performance, but should hold:
+        #  assert len(nblocs) == nb.shape[0], (len(nblocs), nb.shape)
+        #  assert all(x in locs.as_array for x in nb.mgr_locs.as_array)
+
+
+def _get_same_shape_values(
+    lblk: Block, rblk: Block, left_ea: bool, right_ea: bool
+) -> tuple[ArrayLike, ArrayLike]:
+    """
+    Slice lblk.values to align with rblk.  Squeeze if we have EAs.
+    """
+    lvals = lblk.values
+    rvals = rblk.values
+
+    # Require that the indexing into lvals be slice-like
+    assert rblk.mgr_locs.is_slice_like, rblk.mgr_locs
+
+    # TODO(EA2D): with 2D EAs only this first clause would be needed
+    if not (left_ea or right_ea):
+        # error: No overload variant of "__getitem__" of "ExtensionArray" matches
+        # argument type "Tuple[Union[ndarray, slice], slice]"
+        lvals = lvals[rblk.mgr_locs.indexer, :]  # type: ignore[call-overload]
+        assert lvals.shape == rvals.shape, (lvals.shape, rvals.shape)
+    elif left_ea and right_ea:
+        assert lvals.shape == rvals.shape, (lvals.shape, rvals.shape)
+    elif right_ea:
+        # lvals are 2D, rvals are 1D
+
+        # error: No overload variant of "__getitem__" of "ExtensionArray" matches
+        # argument type "Tuple[Union[ndarray, slice], slice]"
+        lvals = lvals[rblk.mgr_locs.indexer, :]  # type: ignore[call-overload]
+        assert lvals.shape[0] == 1, lvals.shape
+        lvals = lvals[0, :]
+    else:
+        # lvals are 1D, rvals are 2D
+        assert rvals.shape[0] == 1, rvals.shape
+        # error: No overload variant of "__getitem__" of "ExtensionArray" matches
+        # argument type "Tuple[int, slice]"
+        rvals = rvals[0, :]  # type: ignore[call-overload]
+
+    return lvals, rvals
+
+
+def blockwise_all(left: BlockManager, right: BlockManager, op) -> bool:
+    """
+    Blockwise `all` reduction.
+    """
+    for info in _iter_block_pairs(left, right):
+        res = op(info.lvals, info.rvals)
+        if not res:
+            return False
+    return True

venv/lib/python3.10/site-packages/pandas/core/ops/__init__.py

@@ -0,0 +1,93 @@
+"""
+Arithmetic operations for PandasObjects
+
+This is not a public API.
+"""
+from __future__ import annotations
+
+from pandas.core.ops.array_ops import (
+    arithmetic_op,
+    comp_method_OBJECT_ARRAY,
+    comparison_op,
+    fill_binop,
+    get_array_op,
+    logical_op,
+    maybe_prepare_scalar_for_op,
+)
+from pandas.core.ops.common import (
+    get_op_result_name,
+    unpack_zerodim_and_defer,
+)
+from pandas.core.ops.docstrings import make_flex_doc
+from pandas.core.ops.invalid import invalid_comparison
+from pandas.core.ops.mask_ops import (
+    kleene_and,
+    kleene_or,
+    kleene_xor,
+)
+from pandas.core.roperator import (
+    radd,
+    rand_,
+    rdiv,
+    rdivmod,
+    rfloordiv,
+    rmod,
+    rmul,
+    ror_,
+    rpow,
+    rsub,
+    rtruediv,
+    rxor,
+)
+
+# -----------------------------------------------------------------------------
+# constants
+ARITHMETIC_BINOPS: set[str] = {
+    "add",
+    "sub",
+    "mul",
+    "pow",
+    "mod",
+    "floordiv",
+    "truediv",
+    "divmod",
+    "radd",
+    "rsub",
+    "rmul",
+    "rpow",
+    "rmod",
+    "rfloordiv",
+    "rtruediv",
+    "rdivmod",
+}
+
+
+__all__ = [
+    "ARITHMETIC_BINOPS",
+    "arithmetic_op",
+    "comparison_op",
+    "comp_method_OBJECT_ARRAY",
+    "invalid_comparison",
+    "fill_binop",
+    "kleene_and",
+    "kleene_or",
+    "kleene_xor",
+    "logical_op",
+    "make_flex_doc",
+    "radd",
+    "rand_",
+    "rdiv",
+    "rdivmod",
+    "rfloordiv",
+    "rmod",
+    "rmul",
+    "ror_",
+    "rpow",
+    "rsub",
+    "rtruediv",
+    "rxor",
+    "unpack_zerodim_and_defer",
+    "get_op_result_name",
+    "maybe_prepare_scalar_for_op",
+    "get_array_op",
+]