bigframes.pandas.api.typing.DataFrameGroupBy.shift

DataFrameGroupBy.shift(periods=1) → Series

Shift each group by periods observations.

Examples:

For SeriesGroupBy:

>>> lst = ['a', 'a', 'b', 'b']
>>> ser = bpd.Series([1, 2, 3, 4], index=lst)
>>> ser.groupby(level=0).shift(1)
a    <NA>
a       1
b    <NA>
b       3
dtype: Int64

For DataFrameGroupBy:

>>> data = [[1, 2, 3], [1, 5, 6], [2, 5, 8], [2, 6, 9]]
>>> df = bpd.DataFrame(data, columns=["a", "b", "c"],
...                   index=["tuna", "salmon", "catfish", "goldfish"])
>>> df.groupby("a").shift(1)
             b     c
tuna      <NA>  <NA>
salmon       2     3
catfish   <NA>  <NA>
goldfish     5     8

[4 rows x 2 columns]

Parameters:

periods (int, default 1) – Number of periods to shift.

Returns:

Object shifted within each group.

Return type:

bigframes.pandas.DataFrame or bigframes.pandas.Series