>>> import pandas as pd >>> pd.__version__ # on current master '1.1.0.dev0+613.g97c0ce962' >>> df = pd.DataFrame({'key': list('aaabbb'), 'value': [1, 2, 3, 3, 2, 1]}) >>> df key value 0 a 1 1 a 2 2 a 3 3 b 3 4 b 2 5 b 1

>>> df.groupby('key') <pandas.core.groupby.generic.DataFrameGroupBy object at 0x000001C0D32FC400> # DataFrameGroupBy.corrwith has no issues >>> df.groupby('key').corrwith(pd.Series([1,2,3,1,2,3])) value key a 1.0 b -1.0 >>> df.groupby('key')['value'] <pandas.core.groupby.generic.SeriesGroupBy object at 0x000001C0D279BF28> # SeriesGroupBy.corrwith is not implemented >>> df.groupby('key')['value'].corrwith(pd.Series([1, 2, 3, 1, 2, 3])) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "c:\users\xxx\xxx\pandas\pandas\core\groupby\groupby.py", line 580, in __getattr__ f"'{type(self).__name__}' object has no attribute '{attr}'" AttributeError: 'SeriesGroupBy' object has no attribute 'corrwith'

>>> df.groupby('key')['value'].corrwith(pd.Series([1, 2, 3, 1, 2, 3])) value key a 1.0 b -1.0