Prime Number Checker

primechecker.py

#imports square root function and sets start var:
from math import sqrt
use = True
counter = 0

#Takes in user's numbers, and "sorts them out":
print("======================")
print("Pryme Number Checker")
print("github.com/georgeomnet")
print("======================\n")
def startprog():
    primeinput = input("Enter your prime numbers, all seperated by spaces:\n")
    global splitinput
    splitinput = primeinput.split()
    global elementsinarray
    elementsinarray = len(splitinput)
    counter = 0
    global primeslist
    primeslist = []

#Adapted Sieve's Primality Test functions:
def findrange(three, numb, two):
    while three < numb:
        yield three
        three += two
def is_prime(num):
    if num == 2:
        return True
    if (num < 2) or (num % 2 == 0):
        return False
    return all(num % i for i in findrange(3, int(sqrt(num)) + 1, 2))

#Loops until all numbers are tested:
def whileloop():
    global counter
    while counter < int(elementsinarray):
        if (is_prime(int(splitinput[counter]))) == True:
            primeslist.append(int(splitinput[counter]))
        counter = counter + 1

#Prints the primes:
def printans():
    print("The prime(s) in that list were:")
    print(*primeslist, sep=',')
    
#Asks the user whether or not they would like to go again?
def goagain():
    global question
    while question != "y" and question != "n":
        question = input("\nWould you like to go again? y/n\n")
        question = question[0]
        question = question.lower()
        if question == "y":
            print("========================")
        elif question == "n":
            global use
            use = False
        else:
            print("Invalid answer!")

#Runs all the functions in order to work:
while use == True:
    startprog()
    counter = 0
    whileloop()
    printans()
    global question
    question = ""
    goagain()