Playing around with the Birthday Paradox

birthday_paradox.py

import random
from datetime import datetime, timedelta


def convert_integer_to_date(day_number_offset):
    beginning_of_year = datetime(year=2021, month=1, day=1)
    date = beginning_of_year + timedelta(days=day_number_offset)
    date_string = date.strftime("%B %d")
    return date_string


def birthday_paradox(number_of_birthdays):
    birthdays = sorted([random.randint(0, 364) for _ in range(number_of_birthdays)])
    unique_birthdays = set()
    matching_birthdays = []

    for birthday in birthdays:
        if birthday in unique_birthdays:
            matching_birthdays.append(convert_integer_to_date(birthday))
        else:
            unique_birthdays.add(birthday)

    return list(set(matching_birthdays))



def main():
    for i in range(2, 102):
        number_of_matches = 0
        number_of_runs = 1_000

        for j in range(number_of_runs):
            matching_birthdays = birthday_paradox(i)
            # print(f"{j}: {matching_birthdays}")

            if matching_birthdays:
                number_of_matches += 1

        match_percentage = round((number_of_matches / number_of_runs) * 100, 2)

        # print()
        print(f"Number of Birthdays: {i}) - {match_percentage}%")


if __name__ == "__main__":
    main()