如何在 Python 中将用户输入限制为仅整数 [英] How can I limit the user input to only integers in Python

问题描述

我正在尝试进行多项选择调查，允许用户从选项 1-x 中进行选择.我怎样才能做到，如果用户输入数字以外的任何字符，则返回类似这是一个无效答案"的内容

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, return something like "That's an invalid answer"

def Survey():
    print('1) Blue')
    print('2) Red')
    print('3) Yellow')
    question = int(input('Out of these options\(1,2,3), which is your favourite?'))
    if question == 1:
        print('Nice!')
    elif question == 2:
        print('Cool')
    elif question == 3:
        print('Awesome!')
    else:
        print('That\'s not an option!')

推荐答案

你的代码会变成:

def Survey():

    print('1) Blue')
    print('2) Red')
    print('3) Yellow')

    while True:
        try:
            question = int(input('Out of these options\(1,2,3), which is your favourite?'))
            break
        except:
            print("That's not a valid option!")

    if question == 1:
        print('Nice!')
    elif question == 2:
        print('Cool')
    elif question == 3:
        print('Awesome!')
    else:
        print('That\'s not an option!')

它的工作方式是创建一个循环，无限循环直到只输入数字.所以说我输入'1'，它会破坏循环.但是如果我输入Fooey！"except 语句会捕获 WOULD 已引发的错误，并且它会循环，因为它没有被破坏.

The way this works is it makes a loop that will loop infinitely until only numbers are put in. So say I put '1', it would break the loop. But if I put 'Fooey!' the error that WOULD have been raised gets caught by the except statement, and it loops as it hasn't been broken.

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