diff --git a/pandas/tests/groupby/test_grouping.py b/pandas/tests/groupby/test_grouping.py index 1e9c4b446c4d0..bad2e0c048dc8 100644 --- a/pandas/tests/groupby/test_grouping.py +++ b/pandas/tests/groupby/test_grouping.py @@ -562,6 +562,37 @@ def test_groupby_multiindex_tuple(self): result = df.groupby(("b", 1)).groups tm.assert_dict_equal(expected, result) + def test_groupby_multiindex_partial_indexing_equivalence(self): + # GH 17977 + df = DataFrame( + [[1, 2, 3, 4], [3, 4, 5, 6], [1, 4, 2, 3]], + columns=MultiIndex.from_arrays([["a", "b", "b", "c"], [1, 1, 2, 2]]), + ) + + expected_mean = df.groupby([("a", 1)])[[("b", 1), ("b", 2)]].mean() + result_mean = df.groupby([("a", 1)])["b"].mean() + tm.assert_frame_equal(expected_mean, result_mean) + + expected_sum = df.groupby([("a", 1)])[[("b", 1), ("b", 2)]].sum() + result_sum = df.groupby([("a", 1)])["b"].sum() + tm.assert_frame_equal(expected_sum, result_sum) + + expected_count = df.groupby([("a", 1)])[[("b", 1), ("b", 2)]].count() + result_count = df.groupby([("a", 1)])["b"].count() + tm.assert_frame_equal(expected_count, result_count) + + expected_min = df.groupby([("a", 1)])[[("b", 1), ("b", 2)]].min() + result_min = df.groupby([("a", 1)])["b"].min() + tm.assert_frame_equal(expected_min, result_min) + + expected_max = df.groupby([("a", 1)])[[("b", 1), ("b", 2)]].max() + result_max = df.groupby([("a", 1)])["b"].max() + tm.assert_frame_equal(expected_max, result_max) + + expected_groups = df.groupby([("a", 1)])[[("b", 1), ("b", 2)]].groups + result_groups = df.groupby([("a", 1)])["b"].groups + tm.assert_dict_equal(expected_groups, result_groups) + @pytest.mark.parametrize("sort", [True, False]) def test_groupby_level(self, sort, mframe, df): # GH 17537