Preventing a user from entering a string in Python 3

Question

I wrote this in Python 3, but how can I prevent the user from entering a string?

x = int(input("If you want to play with computer, click 0. If you want to play with your friend, click 1. "))

Answer 1

using try/except

while True:
    user_input = input("If you want to play with computer, click 0. If you want to play with your friend, click 1. ")
    try:
        user_input = int(user_input)
        # do something
        break
    except ValueError:
        print("input a valid choice please")