Numpy date utilities

This library provides utility functions to perform conversions and get information about numpy dates quickly.

import datetime
import random

import numpy

import pyinterp


def make_date(samples=10000):
    """Generates random dates."""
    epoch = datetime.datetime(1970, 1, 1)
    delta = datetime.datetime.now() - datetime.datetime(1970, 1, 1)

    pydates = [epoch + random.random() * delta for _ in range(samples)]
    npdates = numpy.array(pydates).astype('datetime64[ns]')

    return npdates

dates = make_date()
print(dates)

['2004-06-15T22:15:13.842235000' '1978-10-12T12:26:42.392722000'
 '2018-06-08T16:09:20.417184000' ... '1975-07-20T04:59:17.432479000'
 '1973-10-08T07:13:16.558973000' '1970-02-06T21:33:13.977613000']

Get the date part as a structured numpy array of three fields: year, month and day:

pyinterp.dateutils.date(dates)

array([(2004,  6, 15), (1978, 10, 12), (2018,  6,  8), ...,
       (1975,  7, 20), (1973, 10,  8), (1970,  2,  6)],
      dtype=[('year', '<i4'), ('month', '<u4'), ('day', '<u4')])

Get the time part as a structured numpy array of three fields: hour, minute and second:

pyinterp.dateutils.time(dates)

array([(22, 15, 13), (12, 26, 42), (16,  9, 20), ..., ( 4, 59, 17),
       ( 7, 13, 16), (21, 33, 13)],
      dtype=[('hour', '<u4'), ('minute', '<u4'), ('second', '<u4')])

Get the ISO calendar of the date as a structured numpy array of three fields: year, weekday and week:

pyinterp.dateutils.isocalendar(dates)

array([(2004, 25, 2), (1978, 41, 4), (2018, 23, 5), ..., (1975, 29, 7),
       (1973, 41, 1), (1970,  6, 5)],
      dtype=[('year', '<i4'), ('week', '<u4'), ('weekday', '<u4')])

Get the week day of the dates (Sunday is 0 … Saturday is 6):

pyinterp.dateutils.weekday(dates)

array([2, 4, 5, ..., 0, 1, 5], dtype=uint32)

Get the timedelta from since January

pyinterp.dateutils.timedelta_since_january(dates)

array([14422513842235000, 24582402392722000, 13709360417184000, ...,
       17297957432479000, 24217996558973000,  3187993977613000],
      dtype='timedelta64[ns]')

Get the dates as datetime.datetime array

pyinterp.dateutils.datetime(dates)

array([datetime.datetime(2004, 6, 15, 22, 15, 13, 842235),
       datetime.datetime(1978, 10, 12, 12, 26, 42, 392722),
       datetime.datetime(2018, 6, 8, 16, 9, 20, 417184), ...,
       datetime.datetime(1975, 7, 20, 4, 59, 17, 432479),
       datetime.datetime(1973, 10, 8, 7, 13, 16, 558973),
       datetime.datetime(1970, 2, 6, 21, 33, 13, 977613)], dtype=object)