r/DailyProgrammer Reverse Factorial

numbers.txt

120
150
3628800
479001600
6
18

reverse_factorial.py

#!usr/bin/env python3
"""
This script is the r/DailyProgrammer Easy Challenge #286 titled
Reverse Factorial.
Author: Christopher Bilger
"""


def reverse_factorial(number):
    """
    Function that will take in a number and return the factorial, if any.
    @param int: number to be converted to factorial
    @return factorial (integer) or None
    """
    counter = 1
    rev_number = number

    while True:
        rev_number = rev_number / counter

        if (rev_number).is_integer():
            if rev_number == 1:
                break
            else:
                counter += 1
        else:
            counter = None
            break

    return counter


def main():
    """
    Main function that will run the reverse factorial code.
    """
    numbers = []

    with open("numbers.txt", "r") as all_numbers:
        for number in all_numbers.readlines():
            numbers.append(int(number))

    for number in numbers:
        if reverse_factorial(number) is None:
            print(str(number) + "   NONE")
        else:
            print(str(number) + " = " + str(reverse_factorial(number)) + "!")


if __name__ == '__main__':
    main()