test_groupby.py 文件源码

def test_first_last_max_min_on_time_data(self):
        # GH 10295
        # Verify that NaT is not in the result of max, min, first and last on
        # Dataframe with datetime or timedelta values.
        from datetime import timedelta as td
        df_test = DataFrame(
            {'dt': [nan, '2015-07-24 10:10', '2015-07-25 11:11',
                    '2015-07-23 12:12', nan],
             'td': [nan, td(days=1), td(days=2), td(days=3), nan]})
        df_test.dt = pd.to_datetime(df_test.dt)
        df_test['group'] = 'A'
        df_ref = df_test[df_test.dt.notnull()]

        grouped_test = df_test.groupby('group')
        grouped_ref = df_ref.groupby('group')

        assert_frame_equal(grouped_ref.max(), grouped_test.max())
        assert_frame_equal(grouped_ref.min(), grouped_test.min())
        assert_frame_equal(grouped_ref.first(), grouped_test.first())
        assert_frame_equal(grouped_ref.last(), grouped_test.last())