Print the number of business days and weekend days in a month

business-days-in-month.py

#!/usr/bin/python3

"""
Print the number of business days and weekend days in a month

Example usage:
$ python ./business-days-in-month.py 2024 2
February, 2024 has 21 weekdays and 8 weekend days

Optional: Make the script executable
$ chmod +x ./business-days-in-month.py
$ ./business-days-in-month.py 2024 2
"""

import argparse
import calendar
import datetime
from collections import defaultdict

WEEKDAYS = ("Monday", "Tuesday", "Wednesday", "Thursday", "Friday")


def main(year, month):
    days_in_month = calendar.monthrange(year, month)[1]
    days = defaultdict(list)

    for i in range(1, days_in_month + 1):
        day = datetime.date(year, month, i)
        key = "weekdays" if day.strftime("%A") in WEEKDAYS else "weekends"
        days[key].append(day)

    month_yr_str = datetime.date(year, month, 1).strftime("%B, %Y")
    num_weekdays = len(days["weekdays"])
    num_weekend_days = len(days["weekends"])
    assert num_weekdays + num_weekend_days == days_in_month
    print(
        f"{month_yr_str} has {num_weekdays} weekdays and {num_weekend_days} weekend days for a total of {days_in_month} days."
    )


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Print the number of business days and weekend days in a month"
    )
    parser.add_argument("year", type=int, help="Year (YYYY)")
    parser.add_argument("month", type=int, help="Month (1-12)")
    args = parser.parse_args()
    main(args.year, args.month)