DOC: Add documentation for groupby.expanding() #61254
Description
Pandas version checks
- I have checked that the issue still exists on the latest versions of the docs on
mainhere
Location of the documentation
"https://pandas.pydata.org/docs/dev/reference/groupby.html"
Documentation problem
There is no reference for DataFrameGroupBy.expanding(), even though it exists in API
E.g. consider working example:
>>> import pandas as pd
>>> pd.__version__
'2.2.3'
>>> data = {"Class": ["A", "A", "A", "B", "B", "B"],"Value": [10, 20, 30, 40, 50, 60],}
>>> df = pd.DataFrame(data)
>>> df
Class Value
0 A 10
1 A 20
2 A 30
3 B 40
4 B 50
5 B 60
>>> expanding_mean = df.groupby("Class").expanding().mean().reset_index(drop=True)
>>> expanding_mean
Value
0 10.0
1 15.0
2 20.0
3 40.0
4 45.0
5 50.0
It's undocumented behaviour
Suggested fix for documentation
Include reference of DataFrameGroupBy.expanding and SeriesGroupBy.expanding, like for DataFrameGroupBy.rolling
and SeriesGroupBy.rolling