Checks if a number is prime in a single line of Python

gistfile1.txt

# Assumes that "a" contains an integer > 2 whose primality needs to be verified
# The algorithm builds a list of factors including the number 2 and all odd numbers 
# up to the square root of "a", and then checks if any of those numbers divides "a" 
# without a remainder - if so then "a" is not prime, else it is
if sum([ True if a%factor == 0 else False for factor in ( [2] + list(range(3,int(math.sqrt(a))+1,2) )) ]): 
  print("Number is composite")
else: 
  print("Number is prime")

def prime_number():
print("This program determines if a number is prime or not.")
print("This program will only accept integers.")
number = input("Please enter the number you want to check over here: ")
number = int(number)
if number > 0:
if number == 3:
print("The number is prime.")
choice = input("Do you want to enter another number? Type 'continue' if you do & 'exit' if you don't: ")
if choice == 'continue':
prime_number()
if choice == 'exit':
return
if choice != 'continue' and choice != 'exit':
print("You have not entered a valid choice so the program will stop running.")
return
if number == 1:
print("One is neither prime nor composite.")
choice = input("Do you want to enter another number? Type 'continue' if you do & 'exit' if you don't: ")
if choice == 'continue':
prime_number()
if choice == 'exit':
return
if choice != 'continue' and choice != 'exit':
print("You have not entered a valid choice so the program will stop running.")
return
if number == 2:
print("The number is prime.")
choice = input("Do you want to enter another number? Type 'continue' if you do & 'exit' if you don't: ")
if choice == 'continue':
prime_number()
if choice == 'exit':
return
if choice != 'continue' and choice != 'exit':
print("You have not entered a valid choice so the program will stop running.")
return

    for x in range(2, number - 1):
        if number % x != 0:
            continue
        elif number % x == 0:
            print("The number is not prime.")
            choice = input("Do you want to enter another number? Type 'continue' if you do & 'exit' if you don't: ")
            if choice == 'continue':
                prime_number()
            if choice == 'exit':
                return
            if choice != 'continue' and choice != 'exit':
                print("You have not entered a valid choice so the program will stop running.")
                return

        else:
            print("The number is prime.")
            choice = input("Do you want to enter another number? Type 'continue' if you do & 'exit' if you don't: ")
            if choice == 'continue':
                prime_number()
            if choice == 'exit':
                return
            if choice != 'continue' and choice != 'exit':
                print("You have not entered a valid choice so the program will stop running.")
                return
elif number == 0:
    print("The number is not prime.")
    choice = input("Do you want to enter another number? Type 'continue' if you do & 'exit' if you don't: ")
    if choice == 'continue':
        prime_number()
    if choice == 'exit':
        return
    if choice != 'continue' and choice != 'exit':
        print("You have not entered a valid choice so the program will stop running.")
        return
if number < 0:
    print("This number is less than 0. Please enter a positive integer next time.")
    return

prime_number()

another version
yours is creative though

This doesn't work. For instance, 323. 323/17 = 19. The int(math.sqrt(a)) is 17 but range excludes 17. One revision needs to be made.
list(range(3,int(math.sqrt(a)),2) needs to be:
list(range(3,int(math.sqrt(a))+1, 2)

Well spotted @FaradayLab, thank you