fridays_of.py

#!/usr/bin/env python3

# Find 5 friday (4) the 12th's
# python3 fridays_of.py 12 4 5

import datetime
import sys


def make_get_specified_date(start, day_of_month, day_of_week):
    """
    >>> maker = make_get_specified_date(datetime.date.today(), 12, 4)
    >>> next(maker)
    datetime.date(2014, 12, 12)
    """
    one_day = datetime.timedelta(days=1)
    while True:
        if start.day == day_of_month and start.weekday() == day_of_week:
            yield start
        start -= one_day


def find_dates():
    today = datetime.date.today()
    month_day = int(sys.argv[1])
    week_day = int(sys.argv[2])
    max_items = 5
    if len(sys.argv) > 3:
        max_items = int(sys.argv[3])

    get_specified_date = make_get_specified_date(today, month_day, week_day)

    for i in range(0, max_items):
        print(next(get_specified_date))

if __name__ == '__main__':
    if len(sys.argv) == 1:
        import doctest
        sys.exit(doctest.testmod()[0])
    else:
        find_dates()