BPt.Dataset.last#

Dataset.last(offset)[source]#

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

For a DataFrame with a sorted DatetimeIndex, this function selects the last few rows based on a date offset.

Parameters

offsetstr, DateOffset, dateutil.relativedelta: The offset length of the data that will be selected. For instance, ‘3D’ will display all the rows having their index within the last 3 days.

Returns

Series or DataFrame: A subset of the caller.

Raises

TypeError: If the index is not a DatetimeIndex

See also

first: Select initial periods of time series based on a date offset.
at_time: Select values at a particular time of the day.
between_time: Select values between particular times of the day.

Examples

>>> i = pd.date_range('2018-04-09', periods=4, freq='2D')
>>> ts = pd.DataFrame({'A': [1, 2, 3, 4]}, index=i)
>>> ts
            A
2018-04-09  1
2018-04-11  2
2018-04-13  3
2018-04-15  4

Get the rows for the last 3 days:

>>> ts.last('3D')
            A
2018-04-13  3
2018-04-15  4

Notice the data for 3 last calendar days were returned, not the last 3 observed days in the dataset, and therefore data for 2018-04-11 was not returned.