Checks if a number is an Armstrong number.

is_armstrong.py

# An armstrong number is a number that is the sum of its own digits raised to the power of number of digits that make up the original number.

import sys

def is_armstrong(n):
    n = int(n)
    sum_result = 0

    # 1. Split the number into it's digits and store them in a list.
    digits = list(str(n))

    # 2. Get length of the number.
    digits_length = len(digits)
    
    # 3. Convert the elements of the 'digits' list to integers in order to perform mathematical operations.
    for iterator in range(len(digits)):
        digits[iterator] = int(digits[iterator])
    
    # 4. Raise the digits to the power of digits_length, e.g: n = 653, then digits_length = 3, therefore 6^3 + 5^3 + 3^3.
    for iterator in digits:
        sum_result += iterator ** digits_length

    # 5. Compare the result of the passed number and the sum_result.
    # e.g: n = 371, digits_length = 3, 3^3 + 7^3 + 1^3 = 371. 371 = 371 => n == sum_result, therefore returning True.
    if n == sum_result:
        return True

    # ... Taking the example above, with n = 653, 6^3 + 5^3 + 3^3 = 368. It'd not return True, because 653 != 368. Therefore, it would return False.
    return False
    
# HOW TO RUN: $ py armstrongNumber.py n, where n is the number to check for... armstrongness.
if __name__ == "__main__:
    print(is_armstrong(sys.argv[1]))