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