Series.first(offset: Union[str, pandas._libs.tslibs.offsets.DateOffset]) → pyspark.pandas.series.Series[source]

Select first periods of time series data based on a date offset.

When having a Series with dates as index, this function can select the first few elements based on a date offset.

offsetstr or DateOffset

The offset length of the data that will be selected. For instance, ‘3D’ will display all the rows having their index within the first 3 days.


A subset of the caller.


If the index is not a DatetimeIndex


>>> index = pd.date_range('2018-04-09', periods=4, freq='2D')
>>> psser = ps.Series([1, 2, 3, 4], index=index)
>>> psser
2018-04-09    1
2018-04-11    2
2018-04-13    3
2018-04-15    4
dtype: int64

Get the rows for the first 3 days:

>>> psser.first('3D')
2018-04-09    1
2018-04-11    2
dtype: int64

Notice the data for 3 first calendar days were returned, not the first 3 observed days in the dataset, and therefore data for 2018-04-13 was not returned.