join date with time pandas code example
Example 1: datediff in seconds in pandas
t1 = pd.to_datetime('1/1/2015 01:00')
t2 = pd.to_datetime('1/1/2015 03:30')
print pd.Timedelta(t2 - t1).seconds / 3600.0
Example 2: pandas set hour for timestamp
In [18]: ts
Out[18]: Timestamp('2014-11-12 13:35:00')
In [19]: ts.replace(hour=0)
Out[19]: Timestamp('2014-11-12 00:35:00')