How to round a Pandas `DatetimeIndex`?

Question

I have a pandas.DatetimeIndex, e.g.:

pd.date_range(\'2012-1-1 02:03:04.000\',periods=3,freq=\'1ms\')
>>> [2012-01-01 02:03:04, ..., 201         


        

Answer 1

There is little point in changing the index itself - since you can just generate using date_range with the desired frequency parameter as in your question.

I assume what you are trying to do is change the frequency of a Time Series that contains data, in which case you can use resample (documentation). For example if you have the following time series:

dt_index = pd.date_range('2012-1-1 00:00.001',periods=3, freq='1ms')
ts = pd.Series(randn(3), index=dt_index)


2012-01-01 00:00:00           0.594618
2012-01-01 00:00:00.001000    0.874552
2012-01-01 00:00:00.002000   -0.700076
Freq: L

Then you can change the frequency to seconds using resample, specifying how you want to aggregate the values (mean, sum etc.):

ts.resample('S', how='sum')

2012-01-01 00:00:00    0.594618
2012-01-01 00:00:01    0.174475
Freq: S