A simple script to get the list of Mondays, Tuesdays, etc. for a given date period.

dates_of_certain_day_of_week.py

#!/usr/bin/env python
"""Print the dates of certain day of week given date range."""
import argparse
from datetime import date

import pandas as pd


def parse_dayofweek(dow):
    """Return pandas frequency string from day of the week name."""
    dow_dict = {
        "sun": "W-SUN",
        "mon": "W-MON",
        "tue": "W-TUE",
        "wed": "W-WED",
        "thu": "W-THU",
        "fri": "W-FRI",
        "sat": "W-SAT",
        "sunday": "W-SUN",
        "monday": "W-MON",
        "tuesday": "W-TUE",
        "wednesday": "W-WED",
        "thursday": "W-THU",
        "friday": "W-FRI",
        "saturday": "W-SAT",
    }
    return dow_dict[dow]


def all_days(dow, start_date, end_date):
    """Create a date range for certain day of the week."""
    return (
        pd.date_range(start=start_date, end=end_date, freq=dow)
        .strftime("%m/%d")
        .tolist()
    )


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Return all dates (e.g. Mondays).")
    parser.add_argument(
        "dow",
        default="mon",
        nargs="?",
        help="Day of the week, e.g. 'Mon' or 'Monday'. The default value is Monday.",
    )
    parser.add_argument(
        "-e",
        "--end_date",
        default=date(date.today().year, 12, 31).isoformat(),
        help="Last date. e.g. '2020-12-31' The default is the end of this year.",
    )
    parser.add_argument(
        "-s",
        "--start_date",
        default=date.today().isoformat(),
        help="The first date. e.g. '2020-01-01'. The default is today.",
    )

    args = parser.parse_args()

    for x in all_days(
        parse_dayofweek(args.dow.lower()), args.start_date, args.end_date
    ):
        print(x)