Making a GCF calculator in python

Question

I'm making a calculator in python that takes in two numbers and returns the greatest common factor of it. When I create a function that returns the same numbers of the two lists of factors, I keep getting a 'index' error even if I stated

if len(one) == 0 and len(two) == 0:

here's my code:

def work(one, two):
        for i in range(len(one)):
            for j in range(len(two)):
                if len(one) != 0 and len(two) != 0:
                    if one[i] == two[j]:
                        one.pop(i)
                        two.pop(j)
                        if len(one) == 0 or len(two) == 0:
                            break
                        else:
                            work(primeF, primeF2)
            break
work(primeF, primeF2)

What could I do to fix this?

Answer 1

I think that instead of checking whether the list length is 0, you need to be checking that the list is long enough to include your index.

Answer 2

There is an even easier way to do it without modules (I just used time for supplements)

import time

def gcf (num1, num2): #The Actual Calculator
    if num1 > num2:
        num1, num2 = num2, num1

    for x in range (num1, 0, -1):
        if num1 % x == 0 and num2 % x == 0:
            return x


def run(): #This section is defined so that it can be run multiple times       
    num1 = int(input("First Number: "))  #First number
    num2 = int(input("Second Number: ")) #Second number

    print (str (gcf (num1, num2)))

    run_again = input("Run again? y or yes for yes: ")

    if run_again == "yes" or run_again == "Y" or run_again == "Yes" or 
    run_again == "y": 
        run()
    elif run_again == "hello":
        print("hi")
        run()
    else:
        print("Goodbye!")
        time.sleep(1.5)
        quit()

#Runs the code
run()