A command-line tool to work with dates

daterange.py

#/usr/bin/env python

import sys, argparse, pytz
from datetime import datetime, timedelta

DEFAULT_DATETIME_FORMAT = '%Y%m%d'
SECONDS_IN_A_DAY = 3600 * 24

def main():
    parser = argparse.ArgumentParser(description='A command-line tool to work with dates')
    parser.add_argument('-a', '--range-start', help='the range start (inclusive)', required=True)
    parser.add_argument('-o', '--range-stop', help='the range stop (exclusive)', required=True)
    parser.add_argument('-e', '--range-step', default=SECONDS_IN_A_DAY, type=int, help='the range step, always in seconds')
    parser.add_argument('-f', '--datetime-format', default=DEFAULT_DATETIME_FORMAT, help='the input and output datetime format, for details see: https://docs.python.org/2/library/datetime.html#strftime-strptime-behavior')
    args = parser.parse_args()

    range_start = datetime.strptime(args.range_start, args.datetime_format).replace(tzinfo=pytz.UTC)
    range_stop = datetime.strptime(args.range_stop, args.datetime_format).replace(tzinfo=pytz.UTC)
    range_step = timedelta(seconds=args.range_step)
    print_range(generate_range(range_start, range_stop, range_step), args.datetime_format)

def generate_range(start, stop, step):
    result = []
    d = start
    while d < stop:
        result.append(d)
        d += step
    return result

def print_range(datetime_range, datetime_format):
    for d in datetime_range:
        print(d.strftime(datetime_format))

if __name__ == "__main__":
    main()

daterangetests.py

#/usr/bin/env python

from daterange import *
import unittest

class DaterangeTests(unittest.TestCase):

    def test_generate_range(self):
        datetime_format = '%Y-%m-%d'
        range_start = datetime.strptime('2018-02-26', datetime_format).replace(tzinfo=pytz.UTC)
        range_stop = datetime.strptime('2018-03-02', datetime_format).replace(tzinfo=pytz.UTC)
        range_step = timedelta(seconds=SECONDS_IN_A_DAY)
        expected = [
                datetime.strptime('2018-02-26', datetime_format).replace(tzinfo=pytz.UTC),
                datetime.strptime('2018-02-27', datetime_format).replace(tzinfo=pytz.UTC),
                datetime.strptime('2018-02-28', datetime_format).replace(tzinfo=pytz.UTC),
                datetime.strptime('2018-03-01', datetime_format).replace(tzinfo=pytz.UTC)
                ]
        self.failUnless(expected == generate_range(range_start, range_stop, range_step))

def main():
    unittest.main()

if __name__ == "__main__":
    main()

Usage:

$ python daterange.py -a 2018-02-26 -o 2018-03-02 -f '%Y-%m-%d'
2018-02-26
2018-02-27
2018-02-28
2018-03-01