datediffs.py

#!/usr/bin/env python3

# https://docs.python.org/3/library/datetime.html
# https://docs.python.org/3/library/string.html#formatspec

from datetime import date, timedelta


def days_from_now(days: int) -> date:
    return date.today() + timedelta(days=days)


def print_days_between(d1: date, d2: date = None):
    if d2 is None:
        d2 = date.today()
    if d1 > d2:
        d1, d2 = d2, d1
    print('{} days between {} and {}'.format((d2 - d1).days, d1, d2))


def print_days_from_now(days: int):
    delta = '{} days'.format(days)
    target = days_from_now(days).isoformat()
    print('{:<12}{}'.format(delta, target))


if __name__ == '__main__':
    print_days_between(date(2000, 1, 1), date.today())
    print_days_between(date(2038, 1, 19))
    print('----')
    print_days_from_now(-180)
    print_days_from_now(-90)
    print_days_from_now(-30)
    print_days_from_now(-14)
    print_days_from_now(-7)
    print('----')
    print_days_from_now(7)
    print_days_from_now(14)
    print_days_from_now(30)
    print_days_from_now(90)
    print_days_from_now(180)