diff --git "a/env-llmeval/lib/python3.10/site-packages/pandas/tests/frame/test_stack_unstack.py" "b/env-llmeval/lib/python3.10/site-packages/pandas/tests/frame/test_stack_unstack.py" new file mode 100644--- /dev/null +++ "b/env-llmeval/lib/python3.10/site-packages/pandas/tests/frame/test_stack_unstack.py" @@ -0,0 +1,2678 @@ +from datetime import datetime +import itertools +import re + +import numpy as np +import pytest + +from pandas._libs import lib +from pandas.errors import PerformanceWarning + +import pandas as pd +from pandas import ( + DataFrame, + Index, + MultiIndex, + Period, + Series, + Timedelta, + date_range, +) +import pandas._testing as tm +from pandas.core.reshape import reshape as reshape_lib + + +@pytest.fixture(params=[True, False]) +def future_stack(request): + return request.param + + +class TestDataFrameReshape: + def test_stack_unstack(self, float_frame, future_stack): + df = float_frame.copy() + df[:] = np.arange(np.prod(df.shape)).reshape(df.shape) + + stacked = df.stack(future_stack=future_stack) + stacked_df = DataFrame({"foo": stacked, "bar": stacked}) + + unstacked = stacked.unstack() + unstacked_df = stacked_df.unstack() + + tm.assert_frame_equal(unstacked, df) + tm.assert_frame_equal(unstacked_df["bar"], df) + + unstacked_cols = stacked.unstack(0) + unstacked_cols_df = stacked_df.unstack(0) + tm.assert_frame_equal(unstacked_cols.T, df) + tm.assert_frame_equal(unstacked_cols_df["bar"].T, df) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_mixed_level(self, future_stack): + # GH 18310 + levels = [range(3), [3, "a", "b"], [1, 2]] + + # flat columns: + df = DataFrame(1, index=levels[0], columns=levels[1]) + result = df.stack(future_stack=future_stack) + expected = Series(1, index=MultiIndex.from_product(levels[:2])) + tm.assert_series_equal(result, expected) + + # MultiIndex columns: + df = DataFrame(1, index=levels[0], columns=MultiIndex.from_product(levels[1:])) + result = df.stack(1, future_stack=future_stack) + expected = DataFrame( + 1, index=MultiIndex.from_product([levels[0], levels[2]]), columns=levels[1] + ) + tm.assert_frame_equal(result, expected) + + # as above, but used labels in level are actually of homogeneous type + result = df[["a", "b"]].stack(1, future_stack=future_stack) + expected = expected[["a", "b"]] + tm.assert_frame_equal(result, expected) + + def test_unstack_not_consolidated(self, using_array_manager): + # Gh#34708 + df = DataFrame({"x": [1, 2, np.nan], "y": [3.0, 4, np.nan]}) + df2 = df[["x"]] + df2["y"] = df["y"] + if not using_array_manager: + assert len(df2._mgr.blocks) == 2 + + res = df2.unstack() + expected = df.unstack() + tm.assert_series_equal(res, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_unstack_fill(self, future_stack): + # GH #9746: fill_value keyword argument for Series + # and DataFrame unstack + + # From a series + data = Series([1, 2, 4, 5], dtype=np.int16) + data.index = MultiIndex.from_tuples( + [("x", "a"), ("x", "b"), ("y", "b"), ("z", "a")] + ) + + result = data.unstack(fill_value=-1) + expected = DataFrame( + {"a": [1, -1, 5], "b": [2, 4, -1]}, index=["x", "y", "z"], dtype=np.int16 + ) + tm.assert_frame_equal(result, expected) + + # From a series with incorrect data type for fill_value + result = data.unstack(fill_value=0.5) + expected = DataFrame( + {"a": [1, 0.5, 5], "b": [2, 4, 0.5]}, index=["x", "y", "z"], dtype=float + ) + tm.assert_frame_equal(result, expected) + + # GH #13971: fill_value when unstacking multiple levels: + df = DataFrame( + {"x": ["a", "a", "b"], "y": ["j", "k", "j"], "z": [0, 1, 2], "w": [0, 1, 2]} + ).set_index(["x", "y", "z"]) + unstacked = df.unstack(["x", "y"], fill_value=0) + key = ("w", "b", "j") + expected = unstacked[key] + result = Series([0, 0, 2], index=unstacked.index, name=key) + tm.assert_series_equal(result, expected) + + stacked = unstacked.stack(["x", "y"], future_stack=future_stack) + stacked.index = stacked.index.reorder_levels(df.index.names) + # Workaround for GH #17886 (unnecessarily casts to float): + stacked = stacked.astype(np.int64) + result = stacked.loc[df.index] + tm.assert_frame_equal(result, df) + + # From a series + s = df["w"] + result = s.unstack(["x", "y"], fill_value=0) + expected = unstacked["w"] + tm.assert_frame_equal(result, expected) + + def test_unstack_fill_frame(self): + # From a dataframe + rows = [[1, 2], [3, 4], [5, 6], [7, 8]] + df = DataFrame(rows, columns=list("AB"), dtype=np.int32) + df.index = MultiIndex.from_tuples( + [("x", "a"), ("x", "b"), ("y", "b"), ("z", "a")] + ) + + result = df.unstack(fill_value=-1) + + rows = [[1, 3, 2, 4], [-1, 5, -1, 6], [7, -1, 8, -1]] + expected = DataFrame(rows, index=list("xyz"), dtype=np.int32) + expected.columns = MultiIndex.from_tuples( + [("A", "a"), ("A", "b"), ("B", "a"), ("B", "b")] + ) + tm.assert_frame_equal(result, expected) + + # From a mixed type dataframe + df["A"] = df["A"].astype(np.int16) + df["B"] = df["B"].astype(np.float64) + + result = df.unstack(fill_value=-1) + expected["A"] = expected["A"].astype(np.int16) + expected["B"] = expected["B"].astype(np.float64) + tm.assert_frame_equal(result, expected) + + # From a dataframe with incorrect data type for fill_value + result = df.unstack(fill_value=0.5) + + rows = [[1, 3, 2, 4], [0.5, 5, 0.5, 6], [7, 0.5, 8, 0.5]] + expected = DataFrame(rows, index=list("xyz"), dtype=float) + expected.columns = MultiIndex.from_tuples( + [("A", "a"), ("A", "b"), ("B", "a"), ("B", "b")] + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_fill_frame_datetime(self): + # Test unstacking with date times + dv = date_range("2012-01-01", periods=4).values + data = Series(dv) + data.index = MultiIndex.from_tuples( + [("x", "a"), ("x", "b"), ("y", "b"), ("z", "a")] + ) + + result = data.unstack() + expected = DataFrame( + {"a": [dv[0], pd.NaT, dv[3]], "b": [dv[1], dv[2], pd.NaT]}, + index=["x", "y", "z"], + ) + tm.assert_frame_equal(result, expected) + + result = data.unstack(fill_value=dv[0]) + expected = DataFrame( + {"a": [dv[0], dv[0], dv[3]], "b": [dv[1], dv[2], dv[0]]}, + index=["x", "y", "z"], + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_fill_frame_timedelta(self): + # Test unstacking with time deltas + td = [Timedelta(days=i) for i in range(4)] + data = Series(td) + data.index = MultiIndex.from_tuples( + [("x", "a"), ("x", "b"), ("y", "b"), ("z", "a")] + ) + + result = data.unstack() + expected = DataFrame( + {"a": [td[0], pd.NaT, td[3]], "b": [td[1], td[2], pd.NaT]}, + index=["x", "y", "z"], + ) + tm.assert_frame_equal(result, expected) + + result = data.unstack(fill_value=td[1]) + expected = DataFrame( + {"a": [td[0], td[1], td[3]], "b": [td[1], td[2], td[1]]}, + index=["x", "y", "z"], + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_fill_frame_period(self): + # Test unstacking with period + periods = [ + Period("2012-01"), + Period("2012-02"), + Period("2012-03"), + Period("2012-04"), + ] + data = Series(periods) + data.index = MultiIndex.from_tuples( + [("x", "a"), ("x", "b"), ("y", "b"), ("z", "a")] + ) + + result = data.unstack() + expected = DataFrame( + {"a": [periods[0], None, periods[3]], "b": [periods[1], periods[2], None]}, + index=["x", "y", "z"], + ) + tm.assert_frame_equal(result, expected) + + result = data.unstack(fill_value=periods[1]) + expected = DataFrame( + { + "a": [periods[0], periods[1], periods[3]], + "b": [periods[1], periods[2], periods[1]], + }, + index=["x", "y", "z"], + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_fill_frame_categorical(self): + # Test unstacking with categorical + data = Series(["a", "b", "c", "a"], dtype="category") + data.index = MultiIndex.from_tuples( + [("x", "a"), ("x", "b"), ("y", "b"), ("z", "a")] + ) + + # By default missing values will be NaN + result = data.unstack() + expected = DataFrame( + { + "a": pd.Categorical(list("axa"), categories=list("abc")), + "b": pd.Categorical(list("bcx"), categories=list("abc")), + }, + index=list("xyz"), + ) + tm.assert_frame_equal(result, expected) + + # Fill with non-category results in a ValueError + msg = r"Cannot setitem on a Categorical with a new category \(d\)" + with pytest.raises(TypeError, match=msg): + data.unstack(fill_value="d") + + # Fill with category value replaces missing values as expected + result = data.unstack(fill_value="c") + expected = DataFrame( + { + "a": pd.Categorical(list("aca"), categories=list("abc")), + "b": pd.Categorical(list("bcc"), categories=list("abc")), + }, + index=list("xyz"), + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_tuplename_in_multiindex(self): + # GH 19966 + idx = MultiIndex.from_product( + [["a", "b", "c"], [1, 2, 3]], names=[("A", "a"), ("B", "b")] + ) + df = DataFrame({"d": [1] * 9, "e": [2] * 9}, index=idx) + result = df.unstack(("A", "a")) + + expected = DataFrame( + [[1, 1, 1, 2, 2, 2], [1, 1, 1, 2, 2, 2], [1, 1, 1, 2, 2, 2]], + columns=MultiIndex.from_tuples( + [ + ("d", "a"), + ("d", "b"), + ("d", "c"), + ("e", "a"), + ("e", "b"), + ("e", "c"), + ], + names=[None, ("A", "a")], + ), + index=Index([1, 2, 3], name=("B", "b")), + ) + tm.assert_frame_equal(result, expected) + + @pytest.mark.parametrize( + "unstack_idx, expected_values, expected_index, expected_columns", + [ + ( + ("A", "a"), + [[1, 1, 2, 2], [1, 1, 2, 2], [1, 1, 2, 2], [1, 1, 2, 2]], + MultiIndex.from_tuples( + [(1, 3), (1, 4), (2, 3), (2, 4)], names=["B", "C"] + ), + MultiIndex.from_tuples( + [("d", "a"), ("d", "b"), ("e", "a"), ("e", "b")], + names=[None, ("A", "a")], + ), + ), + ( + (("A", "a"), "B"), + [[1, 1, 1, 1, 2, 2, 2, 2], [1, 1, 1, 1, 2, 2, 2, 2]], + Index([3, 4], name="C"), + MultiIndex.from_tuples( + [ + ("d", "a", 1), + ("d", "a", 2), + ("d", "b", 1), + ("d", "b", 2), + ("e", "a", 1), + ("e", "a", 2), + ("e", "b", 1), + ("e", "b", 2), + ], + names=[None, ("A", "a"), "B"], + ), + ), + ], + ) + def test_unstack_mixed_type_name_in_multiindex( + self, unstack_idx, expected_values, expected_index, expected_columns + ): + # GH 19966 + idx = MultiIndex.from_product( + [["a", "b"], [1, 2], [3, 4]], names=[("A", "a"), "B", "C"] + ) + df = DataFrame({"d": [1] * 8, "e": [2] * 8}, index=idx) + result = df.unstack(unstack_idx) + + expected = DataFrame( + expected_values, columns=expected_columns, index=expected_index + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_preserve_dtypes(self): + # Checks fix for #11847 + df = DataFrame( + { + "state": ["IL", "MI", "NC"], + "index": ["a", "b", "c"], + "some_categories": Series(["a", "b", "c"]).astype("category"), + "A": np.random.default_rng(2).random(3), + "B": 1, + "C": "foo", + "D": pd.Timestamp("20010102"), + "E": Series([1.0, 50.0, 100.0]).astype("float32"), + "F": Series([3.0, 4.0, 5.0]).astype("float64"), + "G": False, + "H": Series([1, 200, 923442]).astype("int8"), + } + ) + + def unstack_and_compare(df, column_name): + unstacked1 = df.unstack([column_name]) + unstacked2 = df.unstack(column_name) + tm.assert_frame_equal(unstacked1, unstacked2) + + df1 = df.set_index(["state", "index"]) + unstack_and_compare(df1, "index") + + df1 = df.set_index(["state", "some_categories"]) + unstack_and_compare(df1, "some_categories") + + df1 = df.set_index(["F", "C"]) + unstack_and_compare(df1, "F") + + df1 = df.set_index(["G", "B", "state"]) + unstack_and_compare(df1, "B") + + df1 = df.set_index(["E", "A"]) + unstack_and_compare(df1, "E") + + df1 = df.set_index(["state", "index"]) + s = df1["A"] + unstack_and_compare(s, "index") + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_ints(self, future_stack): + columns = MultiIndex.from_tuples(list(itertools.product(range(3), repeat=3))) + df = DataFrame( + np.random.default_rng(2).standard_normal((30, 27)), columns=columns + ) + + tm.assert_frame_equal( + df.stack(level=[1, 2], future_stack=future_stack), + df.stack(level=1, future_stack=future_stack).stack( + level=1, future_stack=future_stack + ), + ) + tm.assert_frame_equal( + df.stack(level=[-2, -1], future_stack=future_stack), + df.stack(level=1, future_stack=future_stack).stack( + level=1, future_stack=future_stack + ), + ) + + df_named = df.copy() + return_value = df_named.columns.set_names(range(3), inplace=True) + assert return_value is None + + tm.assert_frame_equal( + df_named.stack(level=[1, 2], future_stack=future_stack), + df_named.stack(level=1, future_stack=future_stack).stack( + level=1, future_stack=future_stack + ), + ) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_mixed_levels(self, future_stack): + columns = MultiIndex.from_tuples( + [ + ("A", "cat", "long"), + ("B", "cat", "long"), + ("A", "dog", "short"), + ("B", "dog", "short"), + ], + names=["exp", "animal", "hair_length"], + ) + df = DataFrame( + np.random.default_rng(2).standard_normal((4, 4)), columns=columns + ) + + animal_hair_stacked = df.stack( + level=["animal", "hair_length"], future_stack=future_stack + ) + exp_hair_stacked = df.stack( + level=["exp", "hair_length"], future_stack=future_stack + ) + + # GH #8584: Need to check that stacking works when a number + # is passed that is both a level name and in the range of + # the level numbers + df2 = df.copy() + df2.columns.names = ["exp", "animal", 1] + tm.assert_frame_equal( + df2.stack(level=["animal", 1], future_stack=future_stack), + animal_hair_stacked, + check_names=False, + ) + tm.assert_frame_equal( + df2.stack(level=["exp", 1], future_stack=future_stack), + exp_hair_stacked, + check_names=False, + ) + + # When mixed types are passed and the ints are not level + # names, raise + msg = ( + "level should contain all level names or all level numbers, not " + "a mixture of the two" + ) + with pytest.raises(ValueError, match=msg): + df2.stack(level=["animal", 0], future_stack=future_stack) + + # GH #8584: Having 0 in the level names could raise a + # strange error about lexsort depth + df3 = df.copy() + df3.columns.names = ["exp", "animal", 0] + tm.assert_frame_equal( + df3.stack(level=["animal", 0], future_stack=future_stack), + animal_hair_stacked, + check_names=False, + ) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_int_level_names(self, future_stack): + columns = MultiIndex.from_tuples( + [ + ("A", "cat", "long"), + ("B", "cat", "long"), + ("A", "dog", "short"), + ("B", "dog", "short"), + ], + names=["exp", "animal", "hair_length"], + ) + df = DataFrame( + np.random.default_rng(2).standard_normal((4, 4)), columns=columns + ) + + exp_animal_stacked = df.stack( + level=["exp", "animal"], future_stack=future_stack + ) + animal_hair_stacked = df.stack( + level=["animal", "hair_length"], future_stack=future_stack + ) + exp_hair_stacked = df.stack( + level=["exp", "hair_length"], future_stack=future_stack + ) + + df2 = df.copy() + df2.columns.names = [0, 1, 2] + tm.assert_frame_equal( + df2.stack(level=[1, 2], future_stack=future_stack), + animal_hair_stacked, + check_names=False, + ) + tm.assert_frame_equal( + df2.stack(level=[0, 1], future_stack=future_stack), + exp_animal_stacked, + check_names=False, + ) + tm.assert_frame_equal( + df2.stack(level=[0, 2], future_stack=future_stack), + exp_hair_stacked, + check_names=False, + ) + + # Out-of-order int column names + df3 = df.copy() + df3.columns.names = [2, 0, 1] + tm.assert_frame_equal( + df3.stack(level=[0, 1], future_stack=future_stack), + animal_hair_stacked, + check_names=False, + ) + tm.assert_frame_equal( + df3.stack(level=[2, 0], future_stack=future_stack), + exp_animal_stacked, + check_names=False, + ) + tm.assert_frame_equal( + df3.stack(level=[2, 1], future_stack=future_stack), + exp_hair_stacked, + check_names=False, + ) + + def test_unstack_bool(self): + df = DataFrame( + [False, False], + index=MultiIndex.from_arrays([["a", "b"], ["c", "l"]]), + columns=["col"], + ) + rs = df.unstack() + xp = DataFrame( + np.array([[False, np.nan], [np.nan, False]], dtype=object), + index=["a", "b"], + columns=MultiIndex.from_arrays([["col", "col"], ["c", "l"]]), + ) + tm.assert_frame_equal(rs, xp) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_unstack_level_binding(self, future_stack): + # GH9856 + mi = MultiIndex( + levels=[["foo", "bar"], ["one", "two"], ["a", "b"]], + codes=[[0, 0, 1, 1], [0, 1, 0, 1], [1, 0, 1, 0]], + names=["first", "second", "third"], + ) + s = Series(0, index=mi) + result = s.unstack([1, 2]).stack(0, future_stack=future_stack) + + expected_mi = MultiIndex( + levels=[["foo", "bar"], ["one", "two"]], + codes=[[0, 0, 1, 1], [0, 1, 0, 1]], + names=["first", "second"], + ) + + expected = DataFrame( + np.array( + [[0, np.nan], [np.nan, 0], [0, np.nan], [np.nan, 0]], dtype=np.float64 + ), + index=expected_mi, + columns=Index(["b", "a"], name="third"), + ) + + tm.assert_frame_equal(result, expected) + + def test_unstack_to_series(self, float_frame): + # check reversibility + data = float_frame.unstack() + + assert isinstance(data, Series) + undo = data.unstack().T + tm.assert_frame_equal(undo, float_frame) + + # check NA handling + data = DataFrame({"x": [1, 2, np.nan], "y": [3.0, 4, np.nan]}) + data.index = Index(["a", "b", "c"]) + result = data.unstack() + + midx = MultiIndex( + levels=[["x", "y"], ["a", "b", "c"]], + codes=[[0, 0, 0, 1, 1, 1], [0, 1, 2, 0, 1, 2]], + ) + expected = Series([1, 2, np.nan, 3, 4, np.nan], index=midx) + + tm.assert_series_equal(result, expected) + + # check composability of unstack + old_data = data.copy() + for _ in range(4): + data = data.unstack() + tm.assert_frame_equal(old_data, data) + + def test_unstack_dtypes(self, using_infer_string): + # GH 2929 + rows = [[1, 1, 3, 4], [1, 2, 3, 4], [2, 1, 3, 4], [2, 2, 3, 4]] + + df = DataFrame(rows, columns=list("ABCD")) + result = df.dtypes + expected = Series([np.dtype("int64")] * 4, index=list("ABCD")) + tm.assert_series_equal(result, expected) + + # single dtype + df2 = df.set_index(["A", "B"]) + df3 = df2.unstack("B") + result = df3.dtypes + expected = Series( + [np.dtype("int64")] * 4, + index=MultiIndex.from_arrays( + [["C", "C", "D", "D"], [1, 2, 1, 2]], names=(None, "B") + ), + ) + tm.assert_series_equal(result, expected) + + # mixed + df2 = df.set_index(["A", "B"]) + df2["C"] = 3.0 + df3 = df2.unstack("B") + result = df3.dtypes + expected = Series( + [np.dtype("float64")] * 2 + [np.dtype("int64")] * 2, + index=MultiIndex.from_arrays( + [["C", "C", "D", "D"], [1, 2, 1, 2]], names=(None, "B") + ), + ) + tm.assert_series_equal(result, expected) + df2["D"] = "foo" + df3 = df2.unstack("B") + result = df3.dtypes + dtype = "string" if using_infer_string else np.dtype("object") + expected = Series( + [np.dtype("float64")] * 2 + [dtype] * 2, + index=MultiIndex.from_arrays( + [["C", "C", "D", "D"], [1, 2, 1, 2]], names=(None, "B") + ), + ) + tm.assert_series_equal(result, expected) + + @pytest.mark.parametrize( + "c, d", + ( + (np.zeros(5), np.zeros(5)), + (np.arange(5, dtype="f8"), np.arange(5, 10, dtype="f8")), + ), + ) + def test_unstack_dtypes_mixed_date(self, c, d): + # GH7405 + df = DataFrame( + { + "A": ["a"] * 5, + "C": c, + "D": d, + "B": date_range("2012-01-01", periods=5), + } + ) + + right = df.iloc[:3].copy(deep=True) + + df = df.set_index(["A", "B"]) + df["D"] = df["D"].astype("int64") + + left = df.iloc[:3].unstack(0) + right = right.set_index(["A", "B"]).unstack(0) + right[("D", "a")] = right[("D", "a")].astype("int64") + + assert left.shape == (3, 2) + tm.assert_frame_equal(left, right) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_unstack_non_unique_index_names(self, future_stack): + idx = MultiIndex.from_tuples([("a", "b"), ("c", "d")], names=["c1", "c1"]) + df = DataFrame([1, 2], index=idx) + msg = "The name c1 occurs multiple times, use a level number" + with pytest.raises(ValueError, match=msg): + df.unstack("c1") + + with pytest.raises(ValueError, match=msg): + df.T.stack("c1", future_stack=future_stack) + + def test_unstack_unused_levels(self): + # GH 17845: unused codes in index make unstack() cast int to float + idx = MultiIndex.from_product([["a"], ["A", "B", "C", "D"]])[:-1] + df = DataFrame([[1, 0]] * 3, index=idx) + + result = df.unstack() + exp_col = MultiIndex.from_product([[0, 1], ["A", "B", "C"]]) + expected = DataFrame([[1, 1, 1, 0, 0, 0]], index=["a"], columns=exp_col) + tm.assert_frame_equal(result, expected) + assert (result.columns.levels[1] == idx.levels[1]).all() + + # Unused items on both levels + levels = [[0, 1, 7], [0, 1, 2, 3]] + codes = [[0, 0, 1, 1], [0, 2, 0, 2]] + idx = MultiIndex(levels, codes) + block = np.arange(4).reshape(2, 2) + df = DataFrame(np.concatenate([block, block + 4]), index=idx) + result = df.unstack() + expected = DataFrame( + np.concatenate([block * 2, block * 2 + 1], axis=1), columns=idx + ) + tm.assert_frame_equal(result, expected) + assert (result.columns.levels[1] == idx.levels[1]).all() + + @pytest.mark.parametrize( + "level, idces, col_level, idx_level", + ( + (0, [13, 16, 6, 9, 2, 5, 8, 11], [np.nan, "a", 2], [np.nan, 5, 1]), + (1, [8, 11, 1, 4, 12, 15, 13, 16], [np.nan, 5, 1], [np.nan, "a", 2]), + ), + ) + def test_unstack_unused_levels_mixed_with_nan( + self, level, idces, col_level, idx_level + ): + # With mixed dtype and NaN + levels = [["a", 2, "c"], [1, 3, 5, 7]] + codes = [[0, -1, 1, 1], [0, 2, -1, 2]] + idx = MultiIndex(levels, codes) + data = np.arange(8) + df = DataFrame(data.reshape(4, 2), index=idx) + + result = df.unstack(level=level) + exp_data = np.zeros(18) * np.nan + exp_data[idces] = data + cols = MultiIndex.from_product([[0, 1], col_level]) + expected = DataFrame(exp_data.reshape(3, 6), index=idx_level, columns=cols) + tm.assert_frame_equal(result, expected) + + @pytest.mark.parametrize("cols", [["A", "C"], slice(None)]) + def test_unstack_unused_level(self, cols): + # GH 18562 : unused codes on the unstacked level + df = DataFrame([[2010, "a", "I"], [2011, "b", "II"]], columns=["A", "B", "C"]) + + ind = df.set_index(["A", "B", "C"], drop=False) + selection = ind.loc[(slice(None), slice(None), "I"), cols] + result = selection.unstack() + + expected = ind.iloc[[0]][cols] + expected.columns = MultiIndex.from_product( + [expected.columns, ["I"]], names=[None, "C"] + ) + expected.index = expected.index.droplevel("C") + tm.assert_frame_equal(result, expected) + + def test_unstack_long_index(self): + # PH 32624: Error when using a lot of indices to unstack. + # The error occurred only, if a lot of indices are used. + df = DataFrame( + [[1]], + columns=MultiIndex.from_tuples([[0]], names=["c1"]), + index=MultiIndex.from_tuples( + [[0, 0, 1, 0, 0, 0, 1]], + names=["i1", "i2", "i3", "i4", "i5", "i6", "i7"], + ), + ) + result = df.unstack(["i2", "i3", "i4", "i5", "i6", "i7"]) + expected = DataFrame( + [[1]], + columns=MultiIndex.from_tuples( + [[0, 0, 1, 0, 0, 0, 1]], + names=["c1", "i2", "i3", "i4", "i5", "i6", "i7"], + ), + index=Index([0], name="i1"), + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_multi_level_cols(self): + # PH 24729: Unstack a df with multi level columns + df = DataFrame( + [[0.0, 0.0], [0.0, 0.0]], + columns=MultiIndex.from_tuples( + [["B", "C"], ["B", "D"]], names=["c1", "c2"] + ), + index=MultiIndex.from_tuples( + [[10, 20, 30], [10, 20, 40]], names=["i1", "i2", "i3"] + ), + ) + assert df.unstack(["i2", "i1"]).columns.names[-2:] == ["i2", "i1"] + + def test_unstack_multi_level_rows_and_cols(self): + # PH 28306: Unstack df with multi level cols and rows + df = DataFrame( + [[1, 2], [3, 4], [-1, -2], [-3, -4]], + columns=MultiIndex.from_tuples([["a", "b", "c"], ["d", "e", "f"]]), + index=MultiIndex.from_tuples( + [ + ["m1", "P3", 222], + ["m1", "A5", 111], + ["m2", "P3", 222], + ["m2", "A5", 111], + ], + names=["i1", "i2", "i3"], + ), + ) + result = df.unstack(["i3", "i2"]) + expected = df.unstack(["i3"]).unstack(["i2"]) + tm.assert_frame_equal(result, expected) + + @pytest.mark.parametrize("idx", [("jim", "joe"), ("joe", "jim")]) + @pytest.mark.parametrize("lev", list(range(2))) + def test_unstack_nan_index1(self, idx, lev): + # GH7466 + def cast(val): + val_str = "" if val != val else val + return f"{val_str:1}" + + df = DataFrame( + { + "jim": ["a", "b", np.nan, "d"], + "joe": ["w", "x", "y", "z"], + "jolie": ["a.w", "b.x", " .y", "d.z"], + } + ) + + left = df.set_index(["jim", "joe"]).unstack()["jolie"] + right = df.set_index(["joe", "jim"]).unstack()["jolie"].T + tm.assert_frame_equal(left, right) + + mi = df.set_index(list(idx)) + udf = mi.unstack(level=lev) + assert udf.notna().values.sum() == len(df) + mk_list = lambda a: list(a) if isinstance(a, tuple) else [a] + rows, cols = udf["jolie"].notna().values.nonzero() + for i, j in zip(rows, cols): + left = sorted(udf["jolie"].iloc[i, j].split(".")) + right = mk_list(udf["jolie"].index[i]) + mk_list(udf["jolie"].columns[j]) + right = sorted(map(cast, right)) + assert left == right + + @pytest.mark.parametrize("idx", itertools.permutations(["1st", "2nd", "3rd"])) + @pytest.mark.parametrize("lev", list(range(3))) + @pytest.mark.parametrize("col", ["4th", "5th"]) + def test_unstack_nan_index_repeats(self, idx, lev, col): + def cast(val): + val_str = "" if val != val else val + return f"{val_str:1}" + + df = DataFrame( + { + "1st": ["d"] * 3 + + [np.nan] * 5 + + ["a"] * 2 + + ["c"] * 3 + + ["e"] * 2 + + ["b"] * 5, + "2nd": ["y"] * 2 + + ["w"] * 3 + + [np.nan] * 3 + + ["z"] * 4 + + [np.nan] * 3 + + ["x"] * 3 + + [np.nan] * 2, + "3rd": [ + 67, + 39, + 53, + 72, + 57, + 80, + 31, + 18, + 11, + 30, + 59, + 50, + 62, + 59, + 76, + 52, + 14, + 53, + 60, + 51, + ], + } + ) + + df["4th"], df["5th"] = ( + df.apply(lambda r: ".".join(map(cast, r)), axis=1), + df.apply(lambda r: ".".join(map(cast, r.iloc[::-1])), axis=1), + ) + + mi = df.set_index(list(idx)) + udf = mi.unstack(level=lev) + assert udf.notna().values.sum() == 2 * len(df) + mk_list = lambda a: list(a) if isinstance(a, tuple) else [a] + rows, cols = udf[col].notna().values.nonzero() + for i, j in zip(rows, cols): + left = sorted(udf[col].iloc[i, j].split(".")) + right = mk_list(udf[col].index[i]) + mk_list(udf[col].columns[j]) + right = sorted(map(cast, right)) + assert left == right + + def test_unstack_nan_index2(self): + # GH7403 + df = DataFrame({"A": list("aaaabbbb"), "B": range(8), "C": range(8)}) + # Explicit cast to avoid implicit cast when setting to np.nan + df = df.astype({"B": "float"}) + df.iloc[3, 1] = np.nan + left = df.set_index(["A", "B"]).unstack(0) + + vals = [ + [3, 0, 1, 2, np.nan, np.nan, np.nan, np.nan], + [np.nan, np.nan, np.nan, np.nan, 4, 5, 6, 7], + ] + vals = list(map(list, zip(*vals))) + idx = Index([np.nan, 0, 1, 2, 4, 5, 6, 7], name="B") + cols = MultiIndex( + levels=[["C"], ["a", "b"]], codes=[[0, 0], [0, 1]], names=[None, "A"] + ) + + right = DataFrame(vals, columns=cols, index=idx) + tm.assert_frame_equal(left, right) + + df = DataFrame({"A": list("aaaabbbb"), "B": list(range(4)) * 2, "C": range(8)}) + # Explicit cast to avoid implicit cast when setting to np.nan + df = df.astype({"B": "float"}) + df.iloc[2, 1] = np.nan + left = df.set_index(["A", "B"]).unstack(0) + + vals = [[2, np.nan], [0, 4], [1, 5], [np.nan, 6], [3, 7]] + cols = MultiIndex( + levels=[["C"], ["a", "b"]], codes=[[0, 0], [0, 1]], names=[None, "A"] + ) + idx = Index([np.nan, 0, 1, 2, 3], name="B") + right = DataFrame(vals, columns=cols, index=idx) + tm.assert_frame_equal(left, right) + + df = DataFrame({"A": list("aaaabbbb"), "B": list(range(4)) * 2, "C": range(8)}) + # Explicit cast to avoid implicit cast when setting to np.nan + df = df.astype({"B": "float"}) + df.iloc[3, 1] = np.nan + left = df.set_index(["A", "B"]).unstack(0) + + vals = [[3, np.nan], [0, 4], [1, 5], [2, 6], [np.nan, 7]] + cols = MultiIndex( + levels=[["C"], ["a", "b"]], codes=[[0, 0], [0, 1]], names=[None, "A"] + ) + idx = Index([np.nan, 0, 1, 2, 3], name="B") + right = DataFrame(vals, columns=cols, index=idx) + tm.assert_frame_equal(left, right) + + def test_unstack_nan_index3(self, using_array_manager): + # GH7401 + df = DataFrame( + { + "A": list("aaaaabbbbb"), + "B": (date_range("2012-01-01", periods=5).tolist() * 2), + "C": np.arange(10), + } + ) + + df.iloc[3, 1] = np.nan + left = df.set_index(["A", "B"]).unstack() + + vals = np.array([[3, 0, 1, 2, np.nan, 4], [np.nan, 5, 6, 7, 8, 9]]) + idx = Index(["a", "b"], name="A") + cols = MultiIndex( + levels=[["C"], date_range("2012-01-01", periods=5)], + codes=[[0, 0, 0, 0, 0, 0], [-1, 0, 1, 2, 3, 4]], + names=[None, "B"], + ) + + right = DataFrame(vals, columns=cols, index=idx) + if using_array_manager: + # INFO(ArrayManager) with ArrayManager preserve dtype where possible + cols = right.columns[[1, 2, 3, 5]] + right[cols] = right[cols].astype(df["C"].dtype) + tm.assert_frame_equal(left, right) + + def test_unstack_nan_index4(self): + # GH4862 + vals = [ + ["Hg", np.nan, np.nan, 680585148], + ["U", 0.0, np.nan, 680585148], + ["Pb", 7.07e-06, np.nan, 680585148], + ["Sn", 2.3614e-05, 0.0133, 680607017], + ["Ag", 0.0, 0.0133, 680607017], + ["Hg", -0.00015, 0.0133, 680607017], + ] + df = DataFrame( + vals, + columns=["agent", "change", "dosage", "s_id"], + index=[17263, 17264, 17265, 17266, 17267, 17268], + ) + + left = df.copy().set_index(["s_id", "dosage", "agent"]).unstack() + + vals = [ + [np.nan, np.nan, 7.07e-06, np.nan, 0.0], + [0.0, -0.00015, np.nan, 2.3614e-05, np.nan], + ] + + idx = MultiIndex( + levels=[[680585148, 680607017], [0.0133]], + codes=[[0, 1], [-1, 0]], + names=["s_id", "dosage"], + ) + + cols = MultiIndex( + levels=[["change"], ["Ag", "Hg", "Pb", "Sn", "U"]], + codes=[[0, 0, 0, 0, 0], [0, 1, 2, 3, 4]], + names=[None, "agent"], + ) + + right = DataFrame(vals, columns=cols, index=idx) + tm.assert_frame_equal(left, right) + + left = df.loc[17264:].copy().set_index(["s_id", "dosage", "agent"]) + tm.assert_frame_equal(left.unstack(), right) + + def test_unstack_nan_index5(self): + # GH9497 - multiple unstack with nulls + df = DataFrame( + { + "1st": [1, 2, 1, 2, 1, 2], + "2nd": date_range("2014-02-01", periods=6, freq="D"), + "jim": 100 + np.arange(6), + "joe": (np.random.default_rng(2).standard_normal(6) * 10).round(2), + } + ) + + df["3rd"] = df["2nd"] - pd.Timestamp("2014-02-02") + df.loc[1, "2nd"] = df.loc[3, "2nd"] = np.nan + df.loc[1, "3rd"] = df.loc[4, "3rd"] = np.nan + + left = df.set_index(["1st", "2nd", "3rd"]).unstack(["2nd", "3rd"]) + assert left.notna().values.sum() == 2 * len(df) + + for col in ["jim", "joe"]: + for _, r in df.iterrows(): + key = r["1st"], (col, r["2nd"], r["3rd"]) + assert r[col] == left.loc[key] + + def test_stack_datetime_column_multiIndex(self, future_stack): + # GH 8039 + t = datetime(2014, 1, 1) + df = DataFrame([1, 2, 3, 4], columns=MultiIndex.from_tuples([(t, "A", "B")])) + warn = None if future_stack else FutureWarning + msg = "The previous implementation of stack is deprecated" + with tm.assert_produces_warning(warn, match=msg): + result = df.stack(future_stack=future_stack) + + eidx = MultiIndex.from_product([(0, 1, 2, 3), ("B",)]) + ecols = MultiIndex.from_tuples([(t, "A")]) + expected = DataFrame([1, 2, 3, 4], index=eidx, columns=ecols) + tm.assert_frame_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + @pytest.mark.parametrize( + "multiindex_columns", + [ + [0, 1, 2, 3, 4], + [0, 1, 2, 3], + [0, 1, 2, 4], + [0, 1, 2], + [1, 2, 3], + [2, 3, 4], + [0, 1], + [0, 2], + [0, 3], + [0], + [2], + [4], + [4, 3, 2, 1, 0], + [3, 2, 1, 0], + [4, 2, 1, 0], + [2, 1, 0], + [3, 2, 1], + [4, 3, 2], + [1, 0], + [2, 0], + [3, 0], + ], + ) + @pytest.mark.parametrize("level", (-1, 0, 1, [0, 1], [1, 0])) + def test_stack_partial_multiIndex(self, multiindex_columns, level, future_stack): + # GH 8844 + dropna = False if not future_stack else lib.no_default + full_multiindex = MultiIndex.from_tuples( + [("B", "x"), ("B", "z"), ("A", "y"), ("C", "x"), ("C", "u")], + names=["Upper", "Lower"], + ) + multiindex = full_multiindex[multiindex_columns] + df = DataFrame( + np.arange(3 * len(multiindex)).reshape(3, len(multiindex)), + columns=multiindex, + ) + result = df.stack(level=level, dropna=dropna, future_stack=future_stack) + + if isinstance(level, int) and not future_stack: + # Stacking a single level should not make any all-NaN rows, + # so df.stack(level=level, dropna=False) should be the same + # as df.stack(level=level, dropna=True). + expected = df.stack(level=level, dropna=True, future_stack=future_stack) + if isinstance(expected, Series): + tm.assert_series_equal(result, expected) + else: + tm.assert_frame_equal(result, expected) + + df.columns = MultiIndex.from_tuples( + df.columns.to_numpy(), names=df.columns.names + ) + expected = df.stack(level=level, dropna=dropna, future_stack=future_stack) + if isinstance(expected, Series): + tm.assert_series_equal(result, expected) + else: + tm.assert_frame_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_full_multiIndex(self, future_stack): + # GH 8844 + full_multiindex = MultiIndex.from_tuples( + [("B", "x"), ("B", "z"), ("A", "y"), ("C", "x"), ("C", "u")], + names=["Upper", "Lower"], + ) + df = DataFrame(np.arange(6).reshape(2, 3), columns=full_multiindex[[0, 1, 3]]) + dropna = False if not future_stack else lib.no_default + result = df.stack(dropna=dropna, future_stack=future_stack) + expected = DataFrame( + [[0, 2], [1, np.nan], [3, 5], [4, np.nan]], + index=MultiIndex( + levels=[[0, 1], ["u", "x", "y", "z"]], + codes=[[0, 0, 1, 1], [1, 3, 1, 3]], + names=[None, "Lower"], + ), + columns=Index(["B", "C"], name="Upper"), + ) + expected["B"] = expected["B"].astype(df.dtypes.iloc[0]) + tm.assert_frame_equal(result, expected) + + @pytest.mark.parametrize("ordered", [False, True]) + def test_stack_preserve_categorical_dtype(self, ordered, future_stack): + # GH13854 + cidx = pd.CategoricalIndex(list("yxz"), categories=list("xyz"), ordered=ordered) + df = DataFrame([[10, 11, 12]], columns=cidx) + result = df.stack(future_stack=future_stack) + + # `MultiIndex.from_product` preserves categorical dtype - + # it's tested elsewhere. + midx = MultiIndex.from_product([df.index, cidx]) + expected = Series([10, 11, 12], index=midx) + + tm.assert_series_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + @pytest.mark.parametrize("ordered", [False, True]) + @pytest.mark.parametrize( + "labels,data", + [ + (list("xyz"), [10, 11, 12, 13, 14, 15]), + (list("zyx"), [14, 15, 12, 13, 10, 11]), + ], + ) + def test_stack_multi_preserve_categorical_dtype( + self, ordered, labels, data, future_stack + ): + # GH-36991 + cidx = pd.CategoricalIndex(labels, categories=sorted(labels), ordered=ordered) + cidx2 = pd.CategoricalIndex(["u", "v"], ordered=ordered) + midx = MultiIndex.from_product([cidx, cidx2]) + df = DataFrame([sorted(data)], columns=midx) + result = df.stack([0, 1], future_stack=future_stack) + + labels = labels if future_stack else sorted(labels) + s_cidx = pd.CategoricalIndex(labels, ordered=ordered) + expected_data = sorted(data) if future_stack else data + expected = Series( + expected_data, index=MultiIndex.from_product([[0], s_cidx, cidx2]) + ) + + tm.assert_series_equal(result, expected) + + def test_stack_preserve_categorical_dtype_values(self, future_stack): + # GH-23077 + cat = pd.Categorical(["a", "a", "b", "c"]) + df = DataFrame({"A": cat, "B": cat}) + result = df.stack(future_stack=future_stack) + index = MultiIndex.from_product([[0, 1, 2, 3], ["A", "B"]]) + expected = Series( + pd.Categorical(["a", "a", "a", "a", "b", "b", "c", "c"]), index=index + ) + tm.assert_series_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + @pytest.mark.filterwarnings("ignore:Downcasting object dtype arrays:FutureWarning") + @pytest.mark.parametrize( + "index, columns", + [ + ([0, 0, 1, 1], MultiIndex.from_product([[1, 2], ["a", "b"]])), + ([0, 0, 2, 3], MultiIndex.from_product([[1, 2], ["a", "b"]])), + ([0, 1, 2, 3], MultiIndex.from_product([[1, 2], ["a", "b"]])), + ], + ) + def test_stack_multi_columns_non_unique_index(self, index, columns, future_stack): + # GH-28301 + + df = DataFrame(index=index, columns=columns).fillna(1) + stacked = df.stack(future_stack=future_stack) + new_index = MultiIndex.from_tuples(stacked.index.to_numpy()) + expected = DataFrame( + stacked.to_numpy(), index=new_index, columns=stacked.columns + ) + tm.assert_frame_equal(stacked, expected) + stacked_codes = np.asarray(stacked.index.codes) + expected_codes = np.asarray(new_index.codes) + tm.assert_numpy_array_equal(stacked_codes, expected_codes) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + @pytest.mark.parametrize( + "vals1, vals2, dtype1, dtype2, expected_dtype", + [ + ([1, 2], [3.0, 4.0], "Int64", "Float64", "Float64"), + ([1, 2], ["foo", "bar"], "Int64", "string", "object"), + ], + ) + def test_stack_multi_columns_mixed_extension_types( + self, vals1, vals2, dtype1, dtype2, expected_dtype, future_stack + ): + # GH45740 + df = DataFrame( + { + ("A", 1): Series(vals1, dtype=dtype1), + ("A", 2): Series(vals2, dtype=dtype2), + } + ) + result = df.stack(future_stack=future_stack) + expected = ( + df.astype(object).stack(future_stack=future_stack).astype(expected_dtype) + ) + tm.assert_frame_equal(result, expected) + + @pytest.mark.parametrize("level", [0, 1]) + def test_unstack_mixed_extension_types(self, level): + index = MultiIndex.from_tuples([("A", 0), ("A", 1), ("B", 1)], names=["a", "b"]) + df = DataFrame( + { + "A": pd.array([0, 1, None], dtype="Int64"), + "B": pd.Categorical(["a", "a", "b"]), + }, + index=index, + ) + + result = df.unstack(level=level) + expected = df.astype(object).unstack(level=level) + if level == 0: + expected[("A", "B")] = expected[("A", "B")].fillna(pd.NA) + else: + expected[("A", 0)] = expected[("A", 0)].fillna(pd.NA) + + expected_dtypes = Series( + [df.A.dtype] * 2 + [df.B.dtype] * 2, index=result.columns + ) + tm.assert_series_equal(result.dtypes, expected_dtypes) + tm.assert_frame_equal(result.astype(object), expected) + + @pytest.mark.parametrize("level", [0, "baz"]) + def test_unstack_swaplevel_sortlevel(self, level): + # GH 20994 + mi = MultiIndex.from_product([[0], ["d", "c"]], names=["bar", "baz"]) + df = DataFrame([[0, 2], [1, 3]], index=mi, columns=["B", "A"]) + df.columns.name = "foo" + + expected = DataFrame( + [[3, 1, 2, 0]], + columns=MultiIndex.from_tuples( + [("c", "A"), ("c", "B"), ("d", "A"), ("d", "B")], names=["baz", "foo"] + ), + ) + expected.index.name = "bar" + + result = df.unstack().swaplevel(axis=1).sort_index(axis=1, level=level) + tm.assert_frame_equal(result, expected) + + +@pytest.mark.parametrize("dtype", ["float64", "Float64"]) +def test_unstack_sort_false(frame_or_series, dtype): + # GH 15105 + index = MultiIndex.from_tuples( + [("two", "z", "b"), ("two", "y", "a"), ("one", "z", "b"), ("one", "y", "a")] + ) + obj = frame_or_series(np.arange(1.0, 5.0), index=index, dtype=dtype) + result = obj.unstack(level=-1, sort=False) + + if frame_or_series is DataFrame: + expected_columns = MultiIndex.from_tuples([(0, "b"), (0, "a")]) + else: + expected_columns = ["b", "a"] + expected = DataFrame( + [[1.0, np.nan], [np.nan, 2.0], [3.0, np.nan], [np.nan, 4.0]], + columns=expected_columns, + index=MultiIndex.from_tuples( + [("two", "z"), ("two", "y"), ("one", "z"), ("one", "y")] + ), + dtype=dtype, + ) + tm.assert_frame_equal(result, expected) + + result = obj.unstack(level=[1, 2], sort=False) + + if frame_or_series is DataFrame: + expected_columns = MultiIndex.from_tuples([(0, "z", "b"), (0, "y", "a")]) + else: + expected_columns = MultiIndex.from_tuples([("z", "b"), ("y", "a")]) + expected = DataFrame( + [[1.0, 2.0], [3.0, 4.0]], + index=["two", "one"], + columns=expected_columns, + dtype=dtype, + ) + tm.assert_frame_equal(result, expected) + + +def test_unstack_fill_frame_object(): + # GH12815 Test unstacking with object. + data = Series(["a", "b", "c", "a"], dtype="object") + data.index = MultiIndex.from_tuples( + [("x", "a"), ("x", "b"), ("y", "b"), ("z", "a")] + ) + + # By default missing values will be NaN + result = data.unstack() + expected = DataFrame( + {"a": ["a", np.nan, "a"], "b": ["b", "c", np.nan]}, + index=list("xyz"), + dtype=object, + ) + tm.assert_frame_equal(result, expected) + + # Fill with any value replaces missing values as expected + result = data.unstack(fill_value="d") + expected = DataFrame( + {"a": ["a", "d", "a"], "b": ["b", "c", "d"]}, index=list("xyz"), dtype=object + ) + tm.assert_frame_equal(result, expected) + + +def test_unstack_timezone_aware_values(): + # GH 18338 + df = DataFrame( + { + "timestamp": [pd.Timestamp("2017-08-27 01:00:00.709949+0000", tz="UTC")], + "a": ["a"], + "b": ["b"], + "c": ["c"], + }, + columns=["timestamp", "a", "b", "c"], + ) + result = df.set_index(["a", "b"]).unstack() + expected = DataFrame( + [[pd.Timestamp("2017-08-27 01:00:00.709949+0000", tz="UTC"), "c"]], + index=Index(["a"], name="a"), + columns=MultiIndex( + levels=[["timestamp", "c"], ["b"]], + codes=[[0, 1], [0, 0]], + names=[None, "b"], + ), + ) + tm.assert_frame_equal(result, expected) + + +def test_stack_timezone_aware_values(future_stack): + # GH 19420 + ts = date_range(freq="D", start="20180101", end="20180103", tz="America/New_York") + df = DataFrame({"A": ts}, index=["a", "b", "c"]) + result = df.stack(future_stack=future_stack) + expected = Series( + ts, + index=MultiIndex(levels=[["a", "b", "c"], ["A"]], codes=[[0, 1, 2], [0, 0, 0]]), + ) + tm.assert_series_equal(result, expected) + + +@pytest.mark.filterwarnings("ignore:The previous implementation of stack is deprecated") +@pytest.mark.parametrize("dropna", [True, False, lib.no_default]) +def test_stack_empty_frame(dropna, future_stack): + # GH 36113 + levels = [np.array([], dtype=np.int64), np.array([], dtype=np.int64)] + expected = Series(dtype=np.float64, index=MultiIndex(levels=levels, codes=[[], []])) + if future_stack and dropna is not lib.no_default: + with pytest.raises(ValueError, match="dropna must be unspecified"): + DataFrame(dtype=np.float64).stack(dropna=dropna, future_stack=future_stack) + else: + result = DataFrame(dtype=np.float64).stack( + dropna=dropna, future_stack=future_stack + ) + tm.assert_series_equal(result, expected) + + +@pytest.mark.filterwarnings("ignore:The previous implementation of stack is deprecated") +@pytest.mark.parametrize("dropna", [True, False, lib.no_default]) +@pytest.mark.parametrize("fill_value", [None, 0]) +def test_stack_unstack_empty_frame(dropna, fill_value, future_stack): + # GH 36113 + if future_stack and dropna is not lib.no_default: + with pytest.raises(ValueError, match="dropna must be unspecified"): + DataFrame(dtype=np.int64).stack( + dropna=dropna, future_stack=future_stack + ).unstack(fill_value=fill_value) + else: + result = ( + DataFrame(dtype=np.int64) + .stack(dropna=dropna, future_stack=future_stack) + .unstack(fill_value=fill_value) + ) + expected = DataFrame(dtype=np.int64) + tm.assert_frame_equal(result, expected) + + +def test_unstack_single_index_series(): + # GH 36113 + msg = r"index must be a MultiIndex to unstack.*" + with pytest.raises(ValueError, match=msg): + Series(dtype=np.int64).unstack() + + +def test_unstacking_multi_index_df(): + # see gh-30740 + df = DataFrame( + { + "name": ["Alice", "Bob"], + "score": [9.5, 8], + "employed": [False, True], + "kids": [0, 0], + "gender": ["female", "male"], + } + ) + df = df.set_index(["name", "employed", "kids", "gender"]) + df = df.unstack(["gender"], fill_value=0) + expected = df.unstack("employed", fill_value=0).unstack("kids", fill_value=0) + result = df.unstack(["employed", "kids"], fill_value=0) + expected = DataFrame( + [[9.5, 0.0, 0.0, 0.0], [0.0, 0.0, 0.0, 8.0]], + index=Index(["Alice", "Bob"], name="name"), + columns=MultiIndex.from_tuples( + [ + ("score", "female", False, 0), + ("score", "female", True, 0), + ("score", "male", False, 0), + ("score", "male", True, 0), + ], + names=[None, "gender", "employed", "kids"], + ), + ) + tm.assert_frame_equal(result, expected) + + +@pytest.mark.filterwarnings("ignore:The previous implementation of stack is deprecated") +def test_stack_positional_level_duplicate_column_names(future_stack): + # https://github.com/pandas-dev/pandas/issues/36353 + columns = MultiIndex.from_product([("x", "y"), ("y", "z")], names=["a", "a"]) + df = DataFrame([[1, 1, 1, 1]], columns=columns) + result = df.stack(0, future_stack=future_stack) + + new_columns = Index(["y", "z"], name="a") + new_index = MultiIndex.from_tuples([(0, "x"), (0, "y")], names=[None, "a"]) + expected = DataFrame([[1, 1], [1, 1]], index=new_index, columns=new_columns) + + tm.assert_frame_equal(result, expected) + + +def test_unstack_non_slice_like_blocks(using_array_manager): + # Case where the mgr_locs of a DataFrame's underlying blocks are not slice-like + + mi = MultiIndex.from_product([range(5), ["A", "B", "C"]]) + df = DataFrame( + { + 0: np.random.default_rng(2).standard_normal(15), + 1: np.random.default_rng(2).standard_normal(15).astype(np.int64), + 2: np.random.default_rng(2).standard_normal(15), + 3: np.random.default_rng(2).standard_normal(15), + }, + index=mi, + ) + if not using_array_manager: + assert any(not x.mgr_locs.is_slice_like for x in df._mgr.blocks) + + res = df.unstack() + + expected = pd.concat([df[n].unstack() for n in range(4)], keys=range(4), axis=1) + tm.assert_frame_equal(res, expected) + + +@pytest.mark.filterwarnings("ignore:The previous implementation of stack is deprecated") +def test_stack_sort_false(future_stack): + # GH 15105 + data = [[1, 2, 3.0, 4.0], [2, 3, 4.0, 5.0], [3, 4, np.nan, np.nan]] + df = DataFrame( + data, + columns=MultiIndex( + levels=[["B", "A"], ["x", "y"]], codes=[[0, 0, 1, 1], [0, 1, 0, 1]] + ), + ) + kwargs = {} if future_stack else {"sort": False} + result = df.stack(level=0, future_stack=future_stack, **kwargs) + if future_stack: + expected = DataFrame( + { + "x": [1.0, 3.0, 2.0, 4.0, 3.0, np.nan], + "y": [2.0, 4.0, 3.0, 5.0, 4.0, np.nan], + }, + index=MultiIndex.from_arrays( + [[0, 0, 1, 1, 2, 2], ["B", "A", "B", "A", "B", "A"]] + ), + ) + else: + expected = DataFrame( + {"x": [1.0, 3.0, 2.0, 4.0, 3.0], "y": [2.0, 4.0, 3.0, 5.0, 4.0]}, + index=MultiIndex.from_arrays([[0, 0, 1, 1, 2], ["B", "A", "B", "A", "B"]]), + ) + tm.assert_frame_equal(result, expected) + + # Codes sorted in this call + df = DataFrame( + data, + columns=MultiIndex.from_arrays([["B", "B", "A", "A"], ["x", "y", "x", "y"]]), + ) + kwargs = {} if future_stack else {"sort": False} + result = df.stack(level=0, future_stack=future_stack, **kwargs) + tm.assert_frame_equal(result, expected) + + +@pytest.mark.filterwarnings("ignore:The previous implementation of stack is deprecated") +def test_stack_sort_false_multi_level(future_stack): + # GH 15105 + idx = MultiIndex.from_tuples([("weight", "kg"), ("height", "m")]) + df = DataFrame([[1.0, 2.0], [3.0, 4.0]], index=["cat", "dog"], columns=idx) + kwargs = {} if future_stack else {"sort": False} + result = df.stack([0, 1], future_stack=future_stack, **kwargs) + expected_index = MultiIndex.from_tuples( + [ + ("cat", "weight", "kg"), + ("cat", "height", "m"), + ("dog", "weight", "kg"), + ("dog", "height", "m"), + ] + ) + expected = Series([1.0, 2.0, 3.0, 4.0], index=expected_index) + tm.assert_series_equal(result, expected) + + +class TestStackUnstackMultiLevel: + def test_unstack(self, multiindex_year_month_day_dataframe_random_data): + # just check that it works for now + ymd = multiindex_year_month_day_dataframe_random_data + + unstacked = ymd.unstack() + unstacked.unstack() + + # test that ints work + ymd.astype(int).unstack() + + # test that int32 work + ymd.astype(np.int32).unstack() + + @pytest.mark.parametrize( + "result_rows,result_columns,index_product,expected_row", + [ + ( + [[1, 1, None, None, 30.0, None], [2, 2, None, None, 30.0, None]], + ["ix1", "ix2", "col1", "col2", "col3", "col4"], + 2, + [None, None, 30.0, None], + ), + ( + [[1, 1, None, None, 30.0], [2, 2, None, None, 30.0]], + ["ix1", "ix2", "col1", "col2", "col3"], + 2, + [None, None, 30.0], + ), + ( + [[1, 1, None, None, 30.0], [2, None, None, None, 30.0]], + ["ix1", "ix2", "col1", "col2", "col3"], + None, + [None, None, 30.0], + ), + ], + ) + def test_unstack_partial( + self, result_rows, result_columns, index_product, expected_row + ): + # check for regressions on this issue: + # https://github.com/pandas-dev/pandas/issues/19351 + # make sure DataFrame.unstack() works when its run on a subset of the DataFrame + # and the Index levels contain values that are not present in the subset + result = DataFrame(result_rows, columns=result_columns).set_index( + ["ix1", "ix2"] + ) + result = result.iloc[1:2].unstack("ix2") + expected = DataFrame( + [expected_row], + columns=MultiIndex.from_product( + [result_columns[2:], [index_product]], names=[None, "ix2"] + ), + index=Index([2], name="ix1"), + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_multiple_no_empty_columns(self): + index = MultiIndex.from_tuples( + [(0, "foo", 0), (0, "bar", 0), (1, "baz", 1), (1, "qux", 1)] + ) + + s = Series(np.random.default_rng(2).standard_normal(4), index=index) + + unstacked = s.unstack([1, 2]) + expected = unstacked.dropna(axis=1, how="all") + tm.assert_frame_equal(unstacked, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack(self, multiindex_year_month_day_dataframe_random_data, future_stack): + ymd = multiindex_year_month_day_dataframe_random_data + + # regular roundtrip + unstacked = ymd.unstack() + restacked = unstacked.stack(future_stack=future_stack) + if future_stack: + # NA values in unstacked persist to restacked in version 3 + restacked = restacked.dropna(how="all") + tm.assert_frame_equal(restacked, ymd) + + unlexsorted = ymd.sort_index(level=2) + + unstacked = unlexsorted.unstack(2) + restacked = unstacked.stack(future_stack=future_stack) + if future_stack: + # NA values in unstacked persist to restacked in version 3 + restacked = restacked.dropna(how="all") + tm.assert_frame_equal(restacked.sort_index(level=0), ymd) + + unlexsorted = unlexsorted[::-1] + unstacked = unlexsorted.unstack(1) + restacked = unstacked.stack(future_stack=future_stack).swaplevel(1, 2) + if future_stack: + # NA values in unstacked persist to restacked in version 3 + restacked = restacked.dropna(how="all") + tm.assert_frame_equal(restacked.sort_index(level=0), ymd) + + unlexsorted = unlexsorted.swaplevel(0, 1) + unstacked = unlexsorted.unstack(0).swaplevel(0, 1, axis=1) + restacked = unstacked.stack(0, future_stack=future_stack).swaplevel(1, 2) + if future_stack: + # NA values in unstacked persist to restacked in version 3 + restacked = restacked.dropna(how="all") + tm.assert_frame_equal(restacked.sort_index(level=0), ymd) + + # columns unsorted + unstacked = ymd.unstack() + restacked = unstacked.stack(future_stack=future_stack) + if future_stack: + # NA values in unstacked persist to restacked in version 3 + restacked = restacked.dropna(how="all") + tm.assert_frame_equal(restacked, ymd) + + # more than 2 levels in the columns + unstacked = ymd.unstack(1).unstack(1) + + result = unstacked.stack(1, future_stack=future_stack) + expected = ymd.unstack() + tm.assert_frame_equal(result, expected) + + result = unstacked.stack(2, future_stack=future_stack) + expected = ymd.unstack(1) + tm.assert_frame_equal(result, expected) + + result = unstacked.stack(0, future_stack=future_stack) + expected = ymd.stack(future_stack=future_stack).unstack(1).unstack(1) + tm.assert_frame_equal(result, expected) + + # not all levels present in each echelon + unstacked = ymd.unstack(2).loc[:, ::3] + stacked = unstacked.stack(future_stack=future_stack).stack( + future_stack=future_stack + ) + ymd_stacked = ymd.stack(future_stack=future_stack) + if future_stack: + # NA values in unstacked persist to restacked in version 3 + stacked = stacked.dropna(how="all") + ymd_stacked = ymd_stacked.dropna(how="all") + tm.assert_series_equal(stacked, ymd_stacked.reindex(stacked.index)) + + # stack with negative number + result = ymd.unstack(0).stack(-2, future_stack=future_stack) + expected = ymd.unstack(0).stack(0, future_stack=future_stack) + tm.assert_equal(result, expected) + + @pytest.mark.parametrize( + "idx, columns, exp_idx", + [ + [ + list("abab"), + ["1st", "2nd", "1st"], + MultiIndex( + levels=[["a", "b"], ["1st", "2nd"]], + codes=[np.tile(np.arange(2).repeat(3), 2), np.tile([0, 1, 0], 4)], + ), + ], + [ + MultiIndex.from_tuples((("a", 2), ("b", 1), ("a", 1), ("b", 2))), + ["1st", "2nd", "1st"], + MultiIndex( + levels=[["a", "b"], [1, 2], ["1st", "2nd"]], + codes=[ + np.tile(np.arange(2).repeat(3), 2), + np.repeat([1, 0, 1], [3, 6, 3]), + np.tile([0, 1, 0], 4), + ], + ), + ], + ], + ) + def test_stack_duplicate_index(self, idx, columns, exp_idx, future_stack): + # GH10417 + df = DataFrame( + np.arange(12).reshape(4, 3), + index=idx, + columns=columns, + ) + if future_stack: + msg = "Columns with duplicate values are not supported in stack" + with pytest.raises(ValueError, match=msg): + df.stack(future_stack=future_stack) + else: + result = df.stack(future_stack=future_stack) + expected = Series(np.arange(12), index=exp_idx) + tm.assert_series_equal(result, expected) + assert result.index.is_unique is False + li, ri = result.index, expected.index + tm.assert_index_equal(li, ri) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_unstack_odd_failure(self, future_stack): + mi = MultiIndex.from_arrays( + [ + ["Fri"] * 4 + ["Sat"] * 2 + ["Sun"] * 2 + ["Thu"] * 3, + ["Dinner"] * 2 + ["Lunch"] * 2 + ["Dinner"] * 5 + ["Lunch"] * 2, + ["No", "Yes"] * 4 + ["No", "No", "Yes"], + ], + names=["day", "time", "smoker"], + ) + df = DataFrame( + { + "sum": np.arange(11, dtype="float64"), + "len": np.arange(11, dtype="float64"), + }, + index=mi, + ) + # it works, #2100 + result = df.unstack(2) + + recons = result.stack(future_stack=future_stack) + if future_stack: + # NA values in unstacked persist to restacked in version 3 + recons = recons.dropna(how="all") + tm.assert_frame_equal(recons, df) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_mixed_dtype(self, multiindex_dataframe_random_data, future_stack): + frame = multiindex_dataframe_random_data + + df = frame.T + df["foo", "four"] = "foo" + df = df.sort_index(level=1, axis=1) + + stacked = df.stack(future_stack=future_stack) + result = df["foo"].stack(future_stack=future_stack).sort_index() + tm.assert_series_equal(stacked["foo"], result, check_names=False) + assert result.name is None + assert stacked["bar"].dtype == np.float64 + + def test_unstack_bug(self, future_stack): + df = DataFrame( + { + "state": ["naive", "naive", "naive", "active", "active", "active"], + "exp": ["a", "b", "b", "b", "a", "a"], + "barcode": [1, 2, 3, 4, 1, 3], + "v": ["hi", "hi", "bye", "bye", "bye", "peace"], + "extra": np.arange(6.0), + } + ) + + msg = "DataFrameGroupBy.apply operated on the grouping columns" + with tm.assert_produces_warning(DeprecationWarning, match=msg): + result = df.groupby(["state", "exp", "barcode", "v"]).apply(len) + + unstacked = result.unstack() + restacked = unstacked.stack(future_stack=future_stack) + tm.assert_series_equal(restacked, result.reindex(restacked.index).astype(float)) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_unstack_preserve_names( + self, multiindex_dataframe_random_data, future_stack + ): + frame = multiindex_dataframe_random_data + + unstacked = frame.unstack() + assert unstacked.index.name == "first" + assert unstacked.columns.names == ["exp", "second"] + + restacked = unstacked.stack(future_stack=future_stack) + assert restacked.index.names == frame.index.names + + @pytest.mark.parametrize("method", ["stack", "unstack"]) + def test_stack_unstack_wrong_level_name( + self, method, multiindex_dataframe_random_data, future_stack + ): + # GH 18303 - wrong level name should raise + frame = multiindex_dataframe_random_data + + # A DataFrame with flat axes: + df = frame.loc["foo"] + + kwargs = {"future_stack": future_stack} if method == "stack" else {} + with pytest.raises(KeyError, match="does not match index name"): + getattr(df, method)("mistake", **kwargs) + + if method == "unstack": + # Same on a Series: + s = df.iloc[:, 0] + with pytest.raises(KeyError, match="does not match index name"): + getattr(s, method)("mistake", **kwargs) + + def test_unstack_level_name(self, multiindex_dataframe_random_data): + frame = multiindex_dataframe_random_data + + result = frame.unstack("second") + expected = frame.unstack(level=1) + tm.assert_frame_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_level_name(self, multiindex_dataframe_random_data, future_stack): + frame = multiindex_dataframe_random_data + + unstacked = frame.unstack("second") + result = unstacked.stack("exp", future_stack=future_stack) + expected = frame.unstack().stack(0, future_stack=future_stack) + tm.assert_frame_equal(result, expected) + + result = frame.stack("exp", future_stack=future_stack) + expected = frame.stack(future_stack=future_stack) + tm.assert_series_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_unstack_multiple( + self, multiindex_year_month_day_dataframe_random_data, future_stack + ): + ymd = multiindex_year_month_day_dataframe_random_data + + unstacked = ymd.unstack(["year", "month"]) + expected = ymd.unstack("year").unstack("month") + tm.assert_frame_equal(unstacked, expected) + assert unstacked.columns.names == expected.columns.names + + # series + s = ymd["A"] + s_unstacked = s.unstack(["year", "month"]) + tm.assert_frame_equal(s_unstacked, expected["A"]) + + restacked = unstacked.stack(["year", "month"], future_stack=future_stack) + if future_stack: + # NA values in unstacked persist to restacked in version 3 + restacked = restacked.dropna(how="all") + restacked = restacked.swaplevel(0, 1).swaplevel(1, 2) + restacked = restacked.sort_index(level=0) + + tm.assert_frame_equal(restacked, ymd) + assert restacked.index.names == ymd.index.names + + # GH #451 + unstacked = ymd.unstack([1, 2]) + expected = ymd.unstack(1).unstack(1).dropna(axis=1, how="all") + tm.assert_frame_equal(unstacked, expected) + + unstacked = ymd.unstack([2, 1]) + expected = ymd.unstack(2).unstack(1).dropna(axis=1, how="all") + tm.assert_frame_equal(unstacked, expected.loc[:, unstacked.columns]) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_names_and_numbers( + self, multiindex_year_month_day_dataframe_random_data, future_stack + ): + ymd = multiindex_year_month_day_dataframe_random_data + + unstacked = ymd.unstack(["year", "month"]) + + # Can't use mixture of names and numbers to stack + with pytest.raises(ValueError, match="level should contain"): + unstacked.stack([0, "month"], future_stack=future_stack) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_multiple_out_of_bounds( + self, multiindex_year_month_day_dataframe_random_data, future_stack + ): + # nlevels == 3 + ymd = multiindex_year_month_day_dataframe_random_data + + unstacked = ymd.unstack(["year", "month"]) + + with pytest.raises(IndexError, match="Too many levels"): + unstacked.stack([2, 3], future_stack=future_stack) + with pytest.raises(IndexError, match="not a valid level number"): + unstacked.stack([-4, -3], future_stack=future_stack) + + def test_unstack_period_series(self): + # GH4342 + idx1 = pd.PeriodIndex( + ["2013-01", "2013-01", "2013-02", "2013-02", "2013-03", "2013-03"], + freq="M", + name="period", + ) + idx2 = Index(["A", "B"] * 3, name="str") + value = [1, 2, 3, 4, 5, 6] + + idx = MultiIndex.from_arrays([idx1, idx2]) + s = Series(value, index=idx) + + result1 = s.unstack() + result2 = s.unstack(level=1) + result3 = s.unstack(level=0) + + e_idx = pd.PeriodIndex( + ["2013-01", "2013-02", "2013-03"], freq="M", name="period" + ) + expected = DataFrame( + {"A": [1, 3, 5], "B": [2, 4, 6]}, index=e_idx, columns=["A", "B"] + ) + expected.columns.name = "str" + + tm.assert_frame_equal(result1, expected) + tm.assert_frame_equal(result2, expected) + tm.assert_frame_equal(result3, expected.T) + + idx1 = pd.PeriodIndex( + ["2013-01", "2013-01", "2013-02", "2013-02", "2013-03", "2013-03"], + freq="M", + name="period1", + ) + + idx2 = pd.PeriodIndex( + ["2013-12", "2013-11", "2013-10", "2013-09", "2013-08", "2013-07"], + freq="M", + name="period2", + ) + idx = MultiIndex.from_arrays([idx1, idx2]) + s = Series(value, index=idx) + + result1 = s.unstack() + result2 = s.unstack(level=1) + result3 = s.unstack(level=0) + + e_idx = pd.PeriodIndex( + ["2013-01", "2013-02", "2013-03"], freq="M", name="period1" + ) + e_cols = pd.PeriodIndex( + ["2013-07", "2013-08", "2013-09", "2013-10", "2013-11", "2013-12"], + freq="M", + name="period2", + ) + expected = DataFrame( + [ + [np.nan, np.nan, np.nan, np.nan, 2, 1], + [np.nan, np.nan, 4, 3, np.nan, np.nan], + [6, 5, np.nan, np.nan, np.nan, np.nan], + ], + index=e_idx, + columns=e_cols, + ) + + tm.assert_frame_equal(result1, expected) + tm.assert_frame_equal(result2, expected) + tm.assert_frame_equal(result3, expected.T) + + def test_unstack_period_frame(self): + # GH4342 + idx1 = pd.PeriodIndex( + ["2014-01", "2014-02", "2014-02", "2014-02", "2014-01", "2014-01"], + freq="M", + name="period1", + ) + idx2 = pd.PeriodIndex( + ["2013-12", "2013-12", "2014-02", "2013-10", "2013-10", "2014-02"], + freq="M", + name="period2", + ) + value = {"A": [1, 2, 3, 4, 5, 6], "B": [6, 5, 4, 3, 2, 1]} + idx = MultiIndex.from_arrays([idx1, idx2]) + df = DataFrame(value, index=idx) + + result1 = df.unstack() + result2 = df.unstack(level=1) + result3 = df.unstack(level=0) + + e_1 = pd.PeriodIndex(["2014-01", "2014-02"], freq="M", name="period1") + e_2 = pd.PeriodIndex( + ["2013-10", "2013-12", "2014-02", "2013-10", "2013-12", "2014-02"], + freq="M", + name="period2", + ) + e_cols = MultiIndex.from_arrays(["A A A B B B".split(), e_2]) + expected = DataFrame( + [[5, 1, 6, 2, 6, 1], [4, 2, 3, 3, 5, 4]], index=e_1, columns=e_cols + ) + + tm.assert_frame_equal(result1, expected) + tm.assert_frame_equal(result2, expected) + + e_1 = pd.PeriodIndex( + ["2014-01", "2014-02", "2014-01", "2014-02"], freq="M", name="period1" + ) + e_2 = pd.PeriodIndex( + ["2013-10", "2013-12", "2014-02"], freq="M", name="period2" + ) + e_cols = MultiIndex.from_arrays(["A A B B".split(), e_1]) + expected = DataFrame( + [[5, 4, 2, 3], [1, 2, 6, 5], [6, 3, 1, 4]], index=e_2, columns=e_cols + ) + + tm.assert_frame_equal(result3, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_multiple_bug(self, future_stack): + # bug when some uniques are not present in the data GH#3170 + id_col = ([1] * 3) + ([2] * 3) + name = (["a"] * 3) + (["b"] * 3) + date = pd.to_datetime(["2013-01-03", "2013-01-04", "2013-01-05"] * 2) + var1 = np.random.default_rng(2).integers(0, 100, 6) + df = DataFrame({"ID": id_col, "NAME": name, "DATE": date, "VAR1": var1}) + + multi = df.set_index(["DATE", "ID"]) + multi.columns.name = "Params" + unst = multi.unstack("ID") + msg = re.escape("agg function failed [how->mean,dtype->") + with pytest.raises(TypeError, match=msg): + unst.resample("W-THU").mean() + down = unst.resample("W-THU").mean(numeric_only=True) + rs = down.stack("ID", future_stack=future_stack) + xp = ( + unst.loc[:, ["VAR1"]] + .resample("W-THU") + .mean() + .stack("ID", future_stack=future_stack) + ) + xp.columns.name = "Params" + tm.assert_frame_equal(rs, xp) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_dropna(self, future_stack): + # GH#3997 + df = DataFrame({"A": ["a1", "a2"], "B": ["b1", "b2"], "C": [1, 1]}) + df = df.set_index(["A", "B"]) + + dropna = False if not future_stack else lib.no_default + stacked = df.unstack().stack(dropna=dropna, future_stack=future_stack) + assert len(stacked) > len(stacked.dropna()) + + if future_stack: + with pytest.raises(ValueError, match="dropna must be unspecified"): + df.unstack().stack(dropna=True, future_stack=future_stack) + else: + stacked = df.unstack().stack(dropna=True, future_stack=future_stack) + tm.assert_frame_equal(stacked, stacked.dropna()) + + def test_unstack_multiple_hierarchical(self, future_stack): + df = DataFrame( + index=[ + [0, 0, 0, 0, 1, 1, 1, 1], + [0, 0, 1, 1, 0, 0, 1, 1], + [0, 1, 0, 1, 0, 1, 0, 1], + ], + columns=[[0, 0, 1, 1], [0, 1, 0, 1]], + ) + + df.index.names = ["a", "b", "c"] + df.columns.names = ["d", "e"] + + # it works! + df.unstack(["b", "c"]) + + def test_unstack_sparse_keyspace(self): + # memory problems with naive impl GH#2278 + # Generate Long File & Test Pivot + NUM_ROWS = 1000 + + df = DataFrame( + { + "A": np.random.default_rng(2).integers(100, size=NUM_ROWS), + "B": np.random.default_rng(3).integers(300, size=NUM_ROWS), + "C": np.random.default_rng(4).integers(-7, 7, size=NUM_ROWS), + "D": np.random.default_rng(5).integers(-19, 19, size=NUM_ROWS), + "E": np.random.default_rng(6).integers(3000, size=NUM_ROWS), + "F": np.random.default_rng(7).standard_normal(NUM_ROWS), + } + ) + + idf = df.set_index(["A", "B", "C", "D", "E"]) + + # it works! is sufficient + idf.unstack("E") + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_unstack_unobserved_keys(self, future_stack): + # related to GH#2278 refactoring + levels = [[0, 1], [0, 1, 2, 3]] + codes = [[0, 0, 1, 1], [0, 2, 0, 2]] + + index = MultiIndex(levels, codes) + + df = DataFrame(np.random.default_rng(2).standard_normal((4, 2)), index=index) + + result = df.unstack() + assert len(result.columns) == 4 + + recons = result.stack(future_stack=future_stack) + tm.assert_frame_equal(recons, df) + + @pytest.mark.slow + def test_unstack_number_of_levels_larger_than_int32(self, monkeypatch): + # GH#20601 + # GH 26314: Change ValueError to PerformanceWarning + + class MockUnstacker(reshape_lib._Unstacker): + def __init__(self, *args, **kwargs) -> None: + # __init__ will raise the warning + super().__init__(*args, **kwargs) + raise Exception("Don't compute final result.") + + with monkeypatch.context() as m: + m.setattr(reshape_lib, "_Unstacker", MockUnstacker) + df = DataFrame( + np.zeros((2**16, 2)), + index=[np.arange(2**16), np.arange(2**16)], + ) + msg = "The following operation may generate" + with tm.assert_produces_warning(PerformanceWarning, match=msg): + with pytest.raises(Exception, match="Don't compute final result."): + df.unstack() + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + @pytest.mark.parametrize( + "levels", + itertools.chain.from_iterable( + itertools.product(itertools.permutations([0, 1, 2], width), repeat=2) + for width in [2, 3] + ), + ) + @pytest.mark.parametrize("stack_lev", range(2)) + @pytest.mark.parametrize("sort", [True, False]) + def test_stack_order_with_unsorted_levels( + self, levels, stack_lev, sort, future_stack + ): + # GH#16323 + # deep check for 1-row case + columns = MultiIndex(levels=levels, codes=[[0, 0, 1, 1], [0, 1, 0, 1]]) + df = DataFrame(columns=columns, data=[range(4)]) + kwargs = {} if future_stack else {"sort": sort} + df_stacked = df.stack(stack_lev, future_stack=future_stack, **kwargs) + for row in df.index: + for col in df.columns: + expected = df.loc[row, col] + result_row = row, col[stack_lev] + result_col = col[1 - stack_lev] + result = df_stacked.loc[result_row, result_col] + assert result == expected + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_order_with_unsorted_levels_multi_row(self, future_stack): + # GH#16323 + + # check multi-row case + mi = MultiIndex( + levels=[["A", "C", "B"], ["B", "A", "C"]], + codes=[np.repeat(range(3), 3), np.tile(range(3), 3)], + ) + df = DataFrame( + columns=mi, index=range(5), data=np.arange(5 * len(mi)).reshape(5, -1) + ) + assert all( + df.loc[row, col] + == df.stack(0, future_stack=future_stack).loc[(row, col[0]), col[1]] + for row in df.index + for col in df.columns + ) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_order_with_unsorted_levels_multi_row_2(self, future_stack): + # GH#53636 + levels = ((0, 1), (1, 0)) + stack_lev = 1 + columns = MultiIndex(levels=levels, codes=[[0, 0, 1, 1], [0, 1, 0, 1]]) + df = DataFrame(columns=columns, data=[range(4)], index=[1, 0, 2, 3]) + kwargs = {} if future_stack else {"sort": True} + result = df.stack(stack_lev, future_stack=future_stack, **kwargs) + expected_index = MultiIndex( + levels=[[0, 1, 2, 3], [0, 1]], + codes=[[1, 1, 0, 0, 2, 2, 3, 3], [1, 0, 1, 0, 1, 0, 1, 0]], + ) + expected = DataFrame( + { + 0: [0, 1, 0, 1, 0, 1, 0, 1], + 1: [2, 3, 2, 3, 2, 3, 2, 3], + }, + index=expected_index, + ) + tm.assert_frame_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_unstack_unordered_multiindex(self, future_stack): + # GH# 18265 + values = np.arange(5) + data = np.vstack( + [ + [f"b{x}" for x in values], # b0, b1, .. + [f"a{x}" for x in values], # a0, a1, .. + ] + ) + df = DataFrame(data.T, columns=["b", "a"]) + df.columns.name = "first" + second_level_dict = {"x": df} + multi_level_df = pd.concat(second_level_dict, axis=1) + multi_level_df.columns.names = ["second", "first"] + df = multi_level_df.reindex(sorted(multi_level_df.columns), axis=1) + result = df.stack(["first", "second"], future_stack=future_stack).unstack( + ["first", "second"] + ) + expected = DataFrame( + [["a0", "b0"], ["a1", "b1"], ["a2", "b2"], ["a3", "b3"], ["a4", "b4"]], + index=[0, 1, 2, 3, 4], + columns=MultiIndex.from_tuples( + [("a", "x"), ("b", "x")], names=["first", "second"] + ), + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_preserve_types( + self, multiindex_year_month_day_dataframe_random_data, using_infer_string + ): + # GH#403 + ymd = multiindex_year_month_day_dataframe_random_data + ymd["E"] = "foo" + ymd["F"] = 2 + + unstacked = ymd.unstack("month") + assert unstacked["A", 1].dtype == np.float64 + assert ( + unstacked["E", 1].dtype == np.object_ + if not using_infer_string + else "string" + ) + assert unstacked["F", 1].dtype == np.float64 + + def test_unstack_group_index_overflow(self, future_stack): + codes = np.tile(np.arange(500), 2) + level = np.arange(500) + + index = MultiIndex( + levels=[level] * 8 + [[0, 1]], + codes=[codes] * 8 + [np.arange(2).repeat(500)], + ) + + s = Series(np.arange(1000), index=index) + result = s.unstack() + assert result.shape == (500, 2) + + # test roundtrip + stacked = result.stack(future_stack=future_stack) + tm.assert_series_equal(s, stacked.reindex(s.index)) + + # put it at beginning + index = MultiIndex( + levels=[[0, 1]] + [level] * 8, + codes=[np.arange(2).repeat(500)] + [codes] * 8, + ) + + s = Series(np.arange(1000), index=index) + result = s.unstack(0) + assert result.shape == (500, 2) + + # put it in middle + index = MultiIndex( + levels=[level] * 4 + [[0, 1]] + [level] * 4, + codes=([codes] * 4 + [np.arange(2).repeat(500)] + [codes] * 4), + ) + + s = Series(np.arange(1000), index=index) + result = s.unstack(4) + assert result.shape == (500, 2) + + def test_unstack_with_missing_int_cast_to_float(self, using_array_manager): + # https://github.com/pandas-dev/pandas/issues/37115 + df = DataFrame( + { + "a": ["A", "A", "B"], + "b": ["ca", "cb", "cb"], + "v": [10] * 3, + } + ).set_index(["a", "b"]) + + # add another int column to get 2 blocks + df["is_"] = 1 + if not using_array_manager: + assert len(df._mgr.blocks) == 2 + + result = df.unstack("b") + result[("is_", "ca")] = result[("is_", "ca")].fillna(0) + + expected = DataFrame( + [[10.0, 10.0, 1.0, 1.0], [np.nan, 10.0, 0.0, 1.0]], + index=Index(["A", "B"], name="a"), + columns=MultiIndex.from_tuples( + [("v", "ca"), ("v", "cb"), ("is_", "ca"), ("is_", "cb")], + names=[None, "b"], + ), + ) + if using_array_manager: + # INFO(ArrayManager) with ArrayManager preserve dtype where possible + expected[("v", "cb")] = expected[("v", "cb")].astype("int64") + expected[("is_", "cb")] = expected[("is_", "cb")].astype("int64") + tm.assert_frame_equal(result, expected) + + def test_unstack_with_level_has_nan(self): + # GH 37510 + df1 = DataFrame( + { + "L1": [1, 2, 3, 4], + "L2": [3, 4, 1, 2], + "L3": [1, 1, 1, 1], + "x": [1, 2, 3, 4], + } + ) + df1 = df1.set_index(["L1", "L2", "L3"]) + new_levels = ["n1", "n2", "n3", None] + df1.index = df1.index.set_levels(levels=new_levels, level="L1") + df1.index = df1.index.set_levels(levels=new_levels, level="L2") + + result = df1.unstack("L3")[("x", 1)].sort_index().index + expected = MultiIndex( + levels=[["n1", "n2", "n3", None], ["n1", "n2", "n3", None]], + codes=[[0, 1, 2, 3], [2, 3, 0, 1]], + names=["L1", "L2"], + ) + + tm.assert_index_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_nan_in_multiindex_columns(self, future_stack): + # GH#39481 + df = DataFrame( + np.zeros([1, 5]), + columns=MultiIndex.from_tuples( + [ + (0, None, None), + (0, 2, 0), + (0, 2, 1), + (0, 3, 0), + (0, 3, 1), + ], + ), + ) + result = df.stack(2, future_stack=future_stack) + if future_stack: + index = MultiIndex(levels=[[0], [0.0, 1.0]], codes=[[0, 0, 0], [-1, 0, 1]]) + columns = MultiIndex(levels=[[0], [2, 3]], codes=[[0, 0, 0], [-1, 0, 1]]) + else: + index = Index([(0, None), (0, 0), (0, 1)]) + columns = Index([(0, None), (0, 2), (0, 3)]) + expected = DataFrame( + [[0.0, np.nan, np.nan], [np.nan, 0.0, 0.0], [np.nan, 0.0, 0.0]], + index=index, + columns=columns, + ) + tm.assert_frame_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_multi_level_stack_categorical(self, future_stack): + # GH 15239 + midx = MultiIndex.from_arrays( + [ + ["A"] * 2 + ["B"] * 2, + pd.Categorical(list("abab")), + pd.Categorical(list("ccdd")), + ] + ) + df = DataFrame(np.arange(8).reshape(2, 4), columns=midx) + result = df.stack([1, 2], future_stack=future_stack) + if future_stack: + expected = DataFrame( + [ + [0, np.nan], + [1, np.nan], + [np.nan, 2], + [np.nan, 3], + [4, np.nan], + [5, np.nan], + [np.nan, 6], + [np.nan, 7], + ], + columns=["A", "B"], + index=MultiIndex.from_arrays( + [ + [0] * 4 + [1] * 4, + pd.Categorical(list("abababab")), + pd.Categorical(list("ccddccdd")), + ] + ), + ) + else: + expected = DataFrame( + [ + [0, np.nan], + [np.nan, 2], + [1, np.nan], + [np.nan, 3], + [4, np.nan], + [np.nan, 6], + [5, np.nan], + [np.nan, 7], + ], + columns=["A", "B"], + index=MultiIndex.from_arrays( + [ + [0] * 4 + [1] * 4, + pd.Categorical(list("aabbaabb")), + pd.Categorical(list("cdcdcdcd")), + ] + ), + ) + tm.assert_frame_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_nan_level(self, future_stack): + # GH 9406 + df_nan = DataFrame( + np.arange(4).reshape(2, 2), + columns=MultiIndex.from_tuples( + [("A", np.nan), ("B", "b")], names=["Upper", "Lower"] + ), + index=Index([0, 1], name="Num"), + dtype=np.float64, + ) + result = df_nan.stack(future_stack=future_stack) + if future_stack: + index = MultiIndex( + levels=[[0, 1], [np.nan, "b"]], + codes=[[0, 0, 1, 1], [0, 1, 0, 1]], + names=["Num", "Lower"], + ) + else: + index = MultiIndex.from_tuples( + [(0, np.nan), (0, "b"), (1, np.nan), (1, "b")], names=["Num", "Lower"] + ) + expected = DataFrame( + [[0.0, np.nan], [np.nan, 1], [2.0, np.nan], [np.nan, 3.0]], + columns=Index(["A", "B"], name="Upper"), + index=index, + ) + tm.assert_frame_equal(result, expected) + + def test_unstack_categorical_columns(self): + # GH 14018 + idx = MultiIndex.from_product([["A"], [0, 1]]) + df = DataFrame({"cat": pd.Categorical(["a", "b"])}, index=idx) + result = df.unstack() + expected = DataFrame( + { + 0: pd.Categorical(["a"], categories=["a", "b"]), + 1: pd.Categorical(["b"], categories=["a", "b"]), + }, + index=["A"], + ) + expected.columns = MultiIndex.from_tuples([("cat", 0), ("cat", 1)]) + tm.assert_frame_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_unsorted(self, future_stack): + # GH 16925 + PAE = ["ITA", "FRA"] + VAR = ["A1", "A2"] + TYP = ["CRT", "DBT", "NET"] + MI = MultiIndex.from_product([PAE, VAR, TYP], names=["PAE", "VAR", "TYP"]) + + V = list(range(len(MI))) + DF = DataFrame(data=V, index=MI, columns=["VALUE"]) + + DF = DF.unstack(["VAR", "TYP"]) + DF.columns = DF.columns.droplevel(0) + DF.loc[:, ("A0", "NET")] = 9999 + + result = DF.stack(["VAR", "TYP"], future_stack=future_stack).sort_index() + expected = ( + DF.sort_index(axis=1) + .stack(["VAR", "TYP"], future_stack=future_stack) + .sort_index() + ) + tm.assert_series_equal(result, expected) + + @pytest.mark.filterwarnings( + "ignore:The previous implementation of stack is deprecated" + ) + def test_stack_nullable_dtype(self, future_stack): + # GH#43561 + columns = MultiIndex.from_product( + [["54511", "54515"], ["r", "t_mean"]], names=["station", "element"] + ) + index = Index([1, 2, 3], name="time") + + arr = np.array([[50, 226, 10, 215], [10, 215, 9, 220], [305, 232, 111, 220]]) + df = DataFrame(arr, columns=columns, index=index, dtype=pd.Int64Dtype()) + + result = df.stack("station", future_stack=future_stack) + + expected = ( + df.astype(np.int64) + .stack("station", future_stack=future_stack) + .astype(pd.Int64Dtype()) + ) + tm.assert_frame_equal(result, expected) + + # non-homogeneous case + df[df.columns[0]] = df[df.columns[0]].astype(pd.Float64Dtype()) + result = df.stack("station", future_stack=future_stack) + + expected = DataFrame( + { + "r": pd.array( + [50.0, 10.0, 10.0, 9.0, 305.0, 111.0], dtype=pd.Float64Dtype() + ), + "t_mean": pd.array( + [226, 215, 215, 220, 232, 220], dtype=pd.Int64Dtype() + ), + }, + index=MultiIndex.from_product([index, columns.levels[0]]), + ) + expected.columns.name = "element" + tm.assert_frame_equal(result, expected) + + def test_unstack_mixed_level_names(self): + # GH#48763 + arrays = [["a", "a"], [1, 2], ["red", "blue"]] + idx = MultiIndex.from_arrays(arrays, names=("x", 0, "y")) + df = DataFrame({"m": [1, 2]}, index=idx) + result = df.unstack("x") + expected = DataFrame( + [[1], [2]], + columns=MultiIndex.from_tuples([("m", "a")], names=[None, "x"]), + index=MultiIndex.from_tuples([(1, "red"), (2, "blue")], names=[0, "y"]), + ) + tm.assert_frame_equal(result, expected) + + +def test_stack_tuple_columns(future_stack): + # GH#54948 - test stack when the input has a non-MultiIndex with tuples + df = DataFrame( + [[1, 2, 3], [4, 5, 6], [7, 8, 9]], columns=[("a", 1), ("a", 2), ("b", 1)] + ) + result = df.stack(future_stack=future_stack) + expected = Series( + [1, 2, 3, 4, 5, 6, 7, 8, 9], + index=MultiIndex( + levels=[[0, 1, 2], [("a", 1), ("a", 2), ("b", 1)]], + codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2], [0, 1, 2, 0, 1, 2, 0, 1, 2]], + ), + ) + tm.assert_series_equal(result, expected) + + +@pytest.mark.parametrize( + "dtype, na_value", + [ + ("float64", np.nan), + ("Float64", np.nan), + ("Float64", pd.NA), + ("Int64", pd.NA), + ], +) +@pytest.mark.parametrize("test_multiindex", [True, False]) +def test_stack_preserves_na(dtype, na_value, test_multiindex): + # GH#56573 + if test_multiindex: + index = MultiIndex.from_arrays(2 * [Index([na_value], dtype=dtype)]) + else: + index = Index([na_value], dtype=dtype) + df = DataFrame({"a": [1]}, index=index) + result = df.stack(future_stack=True) + + if test_multiindex: + expected_index = MultiIndex.from_arrays( + [ + Index([na_value], dtype=dtype), + Index([na_value], dtype=dtype), + Index(["a"]), + ] + ) + else: + expected_index = MultiIndex.from_arrays( + [ + Index([na_value], dtype=dtype), + Index(["a"]), + ] + ) + expected = Series(1, index=expected_index) + tm.assert_series_equal(result, expected)