df.groupby(df.group) produces duplicate column for some aggregation functons

[damccorm]

It should be possible to use df.groupby(df.group) or df.groupby('group') and get the same result. Unfortunately for some aggregation functions (max, min, all, any), the former produces an output with an extraneous 'group' column. Note this doesn't happen for some functions, like size.

In groupby, we should check if the the series is one of this dataframe's columns when setting the index:

beam/sdks/python/apache_beam/dataframe/frames.py

Line 156 in cdb882d

return df.set_index(by)

Imported from Jira BEAM-11305. Original Jira may contain additional context.
Reported by: bhulette.