Conditional selection before certain time of day - Pandas dataframe

Question

I have the above dataframe (snippet) and want create a new dataframe which is a conditional selection where I keep only the rows that are timestamped with a time before 15:00:00.

I'm still somewhat new to Pandas / python and have been stuck on this for a while :(

Answer 1

You can use DataFrame.between_time:

start = pd.to_datetime('2015-02-24 11:00')
rng = pd.date_range(start, periods=10, freq='14h')

df = pd.DataFrame({'Date': rng, 'a': range(10)})  
print (df)
                 Date  a
0 2015-02-24 11:00:00  0
1 2015-02-25 01:00:00  1
2 2015-02-25 15:00:00  2
3 2015-02-26 05:00:00  3
4 2015-02-26 19:00:00  4
5 2015-02-27 09:00:00  5
6 2015-02-27 23:00:00  6
7 2015-02-28 13:00:00  7
8 2015-03-01 03:00:00  8
9 2015-03-01 17:00:00  9

df = df.set_index('Date').between_time('00:00:00', '15:00:00')
print (df)
                     a
Date                  
2015-02-24 11:00:00  0
2015-02-25 01:00:00  1
2015-02-25 15:00:00  2
2015-02-26 05:00:00  3
2015-02-27 09:00:00  5
2015-02-28 13:00:00  7
2015-03-01 03:00:00  8

If need exclude 15:00:00 add parameter include_end=False:

df = df.set_index('Date').between_time('00:00:00', '15:00:00', include_end=False)
print (df)
                     a
Date                  
2015-02-24 11:00:00  0
2015-02-25 01:00:00  1
2015-02-26 05:00:00  3
2015-02-27 09:00:00  5
2015-02-28 13:00:00  7
2015-03-01 03:00:00  8