How can I limit the user input to only integers in Python

Question

I\'m trying to make a multiple choice survey that allows the user to pick from options 1-x. How can I make it so that if the user enters any characters besides numbers, retu

Answer 1

I would catch first the ValueError (not integer) exception and check if the answer is acceptable (within 1, 2, 3) or raise another ValueError exception

def survey():
    print('1) Blue')
    print('2) Red')
    print('3) Yellow')

    ans = 0
    while not ans:
        try:
            ans = int(input('Out of these options\(1, 2, 3), which is your favourite?'))
            if ans not in (1, 2, 3):
                raise ValueError
        except ValueError:
            ans = 0
            print("That's not an option!")

    if ans == 1:
        print('Nice!')
    elif ans == 2:
        print('Cool')
    elif ans == 3:
        print('Awesome!')
    return None