test_timeseries.py 文件源码

def test_first_last_valid(self):
        ts = self.ts.copy()
        ts[:5] = np.NaN

        index = ts.first_valid_index()
        self.assertEqual(index, ts.index[5])

        ts[-5:] = np.NaN
        index = ts.last_valid_index()
        self.assertEqual(index, ts.index[-6])

        ts[:] = np.nan
        self.assertIsNone(ts.last_valid_index())
        self.assertIsNone(ts.first_valid_index())

        ser = Series([], index=[])
        self.assertIsNone(ser.last_valid_index())
        self.assertIsNone(ser.first_valid_index())