weekday_frequency.py

import collections
import datetime
import sys

DAYS_OF_WEEK = [
    "Monday",
    "Tuesday",
    "Wednesday",
    "Thursday",
    "Friday",
    "Saturday",
    "Sunday",
]


def weekday_frequency(month, day, start_year=1583, end_year=3000):
    """
    For the given date (month/day combination), calculate and
    return the frequency, in order, of that date falling on each day
    of the week in the range of years given by start_year - end_year
    (inclusive).

    """
    current_year = start_year
    histogram = collections.Counter({day: 0 for day in DAYS_OF_WEEK})
    while current_year <= end_year:
        year_date = datetime.date(current_year, month, day)
        histogram[DAYS_OF_WEEK[year_date.weekday()]] += 1
        current_year += 1
    return histogram.most_common()


if __name__ == "__main__":
    if len(sys.argv) != 3:
        sys.exit("Please provide numeric month and day arguments, in that order.")
    month, day = map(int, sys.argv[1:])
    for weekday, count in weekday_frequency(month, day):
        print(f"{weekday}: {count}")