["python","pandas","dataframe","datetime","group-by"]
Python Pandas Group by date using datetime data

I have a datetime column Date_Time that I wish to groupby without creating a new column. Is this possible? I tried the following and it does not work. df = pd.groupby(df,by=[df['Date_Time'].date()])
resample df.resample('D', on='Date_Time').mean() B Date_Time 2001-10-01 4.5 2001-10-02 6.0 Grouper As suggested by @JosephCottam df.set_index('Date_Time').groupby(pd.Grouper(freq='D')).mean() B Date_Time 2001-10-01 4.5 2001-10-02 6.0 Deprecated uses of TimeGrouper You can set the index to be 'Date_Time' and use pd.TimeGrouper df.set_index('Date_Time').groupby(pd.TimeGrouper('D')).mean().dropna() B Date_Time 2001-10-01 4.5 2001-10-02 6.0