[FIXED] Python Pandas Group by date using datetime data

Issue

I have a column Date_Time that I wish to groupby date time without creating a new column. Is this possible the current code I have does not work.

df = pd.groupby(df,by=[df['Date_Time'].date()])

Solution

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

Answered By - piRSquared