I have two datetimes between which I would like to generate regular intervals of 4 hours (excluding the last interval, which can be less than 4 hours if there are less than 4 hours between the previous timestamp and end
).
I am stuck on interval generation with pandas.date_range
, which only returns the end
timestamp. For example:
import pandas from datetime import datetime start = datetime(2021, 4, 2, 20, 40, 0) end = datetime(2021, 4, 4, 18, 20, 0) dates = pandas.date_range(start=end, end=end, freq='4H') dates DatetimeIndex(['2021-04-04 18:20:00'], dtype='datetime64[ns]', freq='4H')
The aim is to generate a list of datetime pairs such as:
[['2021-04-02 20:40:00', '2021-04-03 00:40:00'], ['2021-04-03 00:40:00', '2021-04-03 04:40:00']...['2021-04-04 16:40:00', '2021-04-04 18:20:00']] #last pair can be cut off by `end`.
What am I doing wrong in the syntax and how would one go about generating a paired list of intervals from using pandas.date_range
?
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Answer
There was a typo (start=end
) that caused dates
to have only 1 value.
But fixing the typo only gives you a flat range of dates. If you want those nested pairs, you could shift dates
by 4 hours and zip()
:
dates = pandas.date_range(start=start, end=end, freq='4H') shift = dates + pandas.Timedelta(hours=4) pairs = list(zip(dates, shift)) # [(Timestamp('2021-04-02 20:40:00', freq='4H'), # Timestamp('2021-04-03 00:40:00', freq='4H')), # (Timestamp('2021-04-03 00:40:00', freq='4H'), # Timestamp('2021-04-03 04:40:00', freq='4H')), # (Timestamp('2021-04-03 04:40:00', freq='4H'), # Timestamp('2021-04-03 08:40:00', freq='4H')), # ...
Or for a list of lists instead of list of tuples:
pairs = list(map(list, zip(dates, shift)))