fix bug where np.bincount default arg minlength must be None for np<1.13 · pandas-dev/pandas@664ddb8 (original) (raw)

`@@ -212,3 +212,14 @@ def test_count_with_datetimelike(self, datetimelike):

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`expected = DataFrame({'y': [2, 1]}, index=['a', 'b'])

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`expected.index.name = "x"

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`assert_frame_equal(expected, res)

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def test_count_with_only_nans_in_first_group(self):

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GH

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df = DataFrame({'A': [np.nan, np.nan], 'B': ['a', 'b'], 'C': [1, 2]})

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result = df.groupby(['A', 'B']).C.count()

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mi = MultiIndex(levels=[[], ['a', 'b']],

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labels=[[], []],

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names=['A', 'B'])

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expected = Series([], index=mi, dtype=np.int64, name='C')

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assert_series_equal(result, expected, check_index_type=False)

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