防止用户在 Python 3 中输入字符串

Question

我是用 Python 3 写的，但是如何防止用户输入字符串呢？

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




Answer 1

使用try/exceptwhile 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")

Answer 2

您可以在整数转换之前添加一个带有 typeisnumeric方法的if 语句，如下所示：strx = input('Enter a number: ')if x.isnumeric(): # Returns True if x is numeric, otherwise False.    int(x) # Cast it and do what you want with it.else: # x isn't numeric    print('You broke the rules, only numeric is accepted.')