Allow DateOffset addition with Series by chris-b1 · Pull Request #10744 · pandas-dev/pandas (original) (raw)

this could be a property of a DateimeIndex, it is equivalent of .time, but returns a much more useful format pd.TimedeltaIndex(i.asi8-i.to_period('D').to_timestamp().asi8), maybe .timedelta (though not that descsriptive)

In [8]: pd.TimedeltaIndex(i.asi8-i.to_period('D').to_timestamp().asi8),
Out[8]: 
(TimedeltaIndex(['15:03:11', '00:58:59', '10:57:42', '04:40:21', '07:42:04', '01:23:36', '21:41:13', '08:43:29', '08:03:53', '05:31:23', 
                 ...
                 '09:22:04', '14:21:48', '05:27:49', '17:05:16', '00:27:34', '07:22:39', '04:57:11', '10:06:38', '15:28:46', '12:00:39'],
                dtype='timedelta64[ns]', length=10000, freq=None),)

In [9]: i.time
Out[9]: 
array([datetime.time(15, 3, 11), datetime.time(0, 58, 59),
       datetime.time(10, 57, 42), ..., datetime.time(10, 6, 38),
       datetime.time(15, 28, 46), datetime.time(12, 0, 39)], dtype=object)

In [10]: %timeit i.time
100 loops, best of 3: 18.9 ms per loop

In [11]: %timeit pd.TimedeltaIndex(i.asi8-i.to_period('D').to_timestamp().asi8),
100 loops, best of 3: 2.55 ms per loop