import pytest import pandas as pd from pandas import MultiIndex import pandas._testing as tm def check_level_names(index, names): assert [level.name for level in index.levels] == list(names) def test_slice_keep_name(): x = MultiIndex.from_tuples([("a", "b"), (1, 2), ("c", "d")], names=["x", "y"]) assert x[1:].names == x.names def test_index_name_retained(): # GH9857 result = pd.DataFrame({"x": [1, 2, 6], "y": [2, 2, 8], "z": [-5, 0, 5]}) result = result.set_index("z") result.loc[10] = [9, 10] df_expected = pd.DataFrame( {"x": [1, 2, 6, 9], "y": [2, 2, 8, 10], "z": [-5, 0, 5, 10]} ) df_expected = df_expected.set_index("z") tm.assert_frame_equal(result, df_expected) def test_changing_names(idx): assert [level.name for level in idx.levels] == ["first", "second"] view = idx.view() copy = idx.copy() shallow_copy = idx._view() # changing names should not change level names on object new_names = [name + "a" for name in idx.names] idx.names = new_names check_level_names(idx, ["firsta", "seconda"]) # and not on copies check_level_names(view, ["first", "second"]) check_level_names(copy, ["first", "second"]) check_level_names(shallow_copy, ["first", "second"]) # and copies shouldn't change original shallow_copy.names = [name + "c" for name in shallow_copy.names] check_level_names(idx, ["firsta", "seconda"]) def test_take_preserve_name(idx): taken = idx.take([3, 0, 1]) assert taken.names == idx.names def test_copy_names(): # Check that adding a "names" parameter to the copy is honored # GH14302 multi_idx = MultiIndex.from_tuples([(1, 2), (3, 4)], names=["MyName1", "MyName2"]) multi_idx1 = multi_idx.copy() assert multi_idx.equals(multi_idx1) assert multi_idx.names == ["MyName1", "MyName2"] assert multi_idx1.names == ["MyName1", "MyName2"] multi_idx2 = multi_idx.copy(names=["NewName1", "NewName2"]) assert multi_idx.equals(multi_idx2) assert multi_idx.names == ["MyName1", "MyName2"] assert multi_idx2.names == ["NewName1", "NewName2"] multi_idx3 = multi_idx.copy(name=["NewName1", "NewName2"]) assert multi_idx.equals(multi_idx3) assert multi_idx.names == ["MyName1", "MyName2"] assert multi_idx3.names == ["NewName1", "NewName2"] # gh-35592 with pytest.raises(ValueError, match="Length of new names must be 2, got 1"): multi_idx.copy(names=["mario"]) with pytest.raises(TypeError, match="MultiIndex.name must be a hashable type"): multi_idx.copy(names=[["mario"], ["luigi"]]) def test_names(idx): # names are assigned in setup assert idx.names == ["first", "second"] level_names = [level.name for level in idx.levels] assert level_names == idx.names # setting bad names on existing index = idx with pytest.raises(ValueError, match="^Length of names"): setattr(index, "names", list(index.names) + ["third"]) with pytest.raises(ValueError, match="^Length of names"): setattr(index, "names", []) # initializing with bad names (should always be equivalent) major_axis, minor_axis = idx.levels major_codes, minor_codes = idx.codes with pytest.raises(ValueError, match="^Length of names"): MultiIndex( levels=[major_axis, minor_axis], codes=[major_codes, minor_codes], names=["first"], ) with pytest.raises(ValueError, match="^Length of names"): MultiIndex( levels=[major_axis, minor_axis], codes=[major_codes, minor_codes], names=["first", "second", "third"], ) # names are assigned on index, but not transferred to the levels index.names = ["a", "b"] level_names = [level.name for level in index.levels] assert level_names == ["a", "b"] def test_duplicate_level_names_access_raises(idx): # GH19029 idx.names = ["foo", "foo"] with pytest.raises(ValueError, match="name foo occurs multiple times"): idx._get_level_number("foo") def test_get_names_from_levels(): idx = MultiIndex.from_product([["a"], [1, 2]], names=["a", "b"]) assert idx.levels[0].name == "a" assert idx.levels[1].name == "b" def test_setting_names_from_levels_raises(): idx = MultiIndex.from_product([["a"], [1, 2]], names=["a", "b"]) with pytest.raises(RuntimeError, match="set_names"): idx.levels[0].name = "foo" with pytest.raises(RuntimeError, match="set_names"): idx.levels[1].name = "foo" new = pd.Series(1, index=idx.levels[0]) with pytest.raises(RuntimeError, match="set_names"): new.index.name = "bar" assert pd.Index._no_setting_name is False assert pd.RangeIndex._no_setting_name is False @pytest.mark.parametrize("func", ["rename", "set_names"]) @pytest.mark.parametrize( "rename_dict, exp_names", [ ({"x": "z"}, ["z", "y", "z"]), ({"x": "z", "y": "x"}, ["z", "x", "z"]), ({"y": "z"}, ["x", "z", "x"]), ({}, ["x", "y", "x"]), ({"z": "a"}, ["x", "y", "x"]), ({"y": "z", "a": "b"}, ["x", "z", "x"]), ], ) def test_name_mi_with_dict_like_duplicate_names(func, rename_dict, exp_names): # GH#20421 mi = MultiIndex.from_arrays([[1, 2], [3, 4], [5, 6]], names=["x", "y", "x"]) result = getattr(mi, func)(rename_dict) expected = MultiIndex.from_arrays([[1, 2], [3, 4], [5, 6]], names=exp_names) tm.assert_index_equal(result, expected) @pytest.mark.parametrize("func", ["rename", "set_names"]) @pytest.mark.parametrize( "rename_dict, exp_names", [ ({"x": "z"}, ["z", "y"]), ({"x": "z", "y": "x"}, ["z", "x"]), ({"a": "z"}, ["x", "y"]), ({}, ["x", "y"]), ], ) def test_name_mi_with_dict_like(func, rename_dict, exp_names): # GH#20421 mi = MultiIndex.from_arrays([[1, 2], [3, 4]], names=["x", "y"]) result = getattr(mi, func)(rename_dict) expected = MultiIndex.from_arrays([[1, 2], [3, 4]], names=exp_names) tm.assert_index_equal(result, expected) def test_index_name_with_dict_like_raising(): # GH#20421 ix = pd.Index([1, 2]) msg = "Can only pass dict-like as `names` for MultiIndex." with pytest.raises(TypeError, match=msg): ix.set_names({"x": "z"}) def test_multiindex_name_and_level_raising(): # GH#20421 mi = MultiIndex.from_arrays([[1, 2], [3, 4]], names=["x", "y"]) with pytest.raises(TypeError, match="Can not pass level for dictlike `names`."): mi.set_names(names={"x": "z"}, level={"x": "z"})