阻止用户在 Python 3 中输入字符串

Question

我在Python 3中写了这个，但是如何防止用户输入字符串？

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

Answer 1

你可以在整数转换之前用str类型的isnumeric方法添加一个if语句，像这样：

x = 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.')

Answer 2

使用 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")

阻止用户在 Python 3 中输入字符串

Preventing a user from entering a string in Python 3

python

input

whitelist

blacklist