在 python 中验证输入

Question

我试图写一个石头剪刀枪程序，其中选择是1，2和3。我想验证输入，以便除这三个选项之外的任何输入都将打印一条消息，指出输入有效，并要求用户重新输入数据。我有一些工作，但是，即使我输入1 2或3，它仍然会打印消息并要求更多输入。print("This program simulates a 'rock paper scissor' game.")print("The rules are as follows: rock beats scissor, paper beats rock, and scissor beats paper. \n")print("This program simulates a 'rock paper scissor' game.")print("The rules are as follows: rock beats scissor, paper beats rock, and scissor beats paper. \n")#get user inputuser_choice = input("Please choose from the following:  \n"                    " 1 for scissor \n"                    " 2 for rock \n"                    " 3 for paper. \n")#validate input so user only enters 1, 2, or 3while user_choice != 1 or user_choice != 2 or user_choice != 3:    user_choice = input("Please enter only '1' for scissor, '2' for rock, or '3' for paper: ")#convert input to int int_user_choice = int(user_choice)

Answer 1

如果要稍后将输入与整数进行比较，则需要将输入从字符串转换为整数。如果你想避免一遍又一遍地重复逻辑，你可以使用列表。

user_choice = int(input("Please choose from the following:  \n"
                    " 1 for scissor \n"
                    " 2 for rock \n"
                    " 3 for paper. \n"))

和

while user_choice not in [1,2,3]

Answer 2

在单个循环中执行整个提示/验证。在满足条件之前，用户无法继续

print("This program simulates a 'rock paper scissor' game.")

print("The rules are as follows: rock beats scissor, paper beats rock, and scissor beats paper. \n")

print("This program simulates a 'rock paper scissor' game.")

print("The rules are as follows: rock beats scissor, paper beats rock, and scissor beats paper. \n")

#get user input

while True:

    user_choice = input("Please choose from the following:  \n"

                    " 1 for scissor \n"

                    " 2 for rock \n"

                    " 3 for paper. \n")

    #validate input so user only enters 1, 2, or 3

    if user_choice in ["1", "2", "3"]:

        int_user_choice = int(user_choice)

        break

Answer 3

您的不正确，因为输入返回字符串类型，并且您正在使用类型int进行检查，因此请在循环中更改类型。此外，如果希望它在其中一种情况下终止，则不能使用，在这种情况下，您必须使用 。orand

print("This program simulates a 'rock paper scissor' game.")

print("The rules are as follows: rock beats scissor, paper beats rock, and scissor beats paper. \n")

print("This program simulates a 'rock paper scissor' game.")

print("The rules are as follows: rock beats scissor, paper beats rock, and scissor beats paper. \n")

#get user input

user_choice = input("Please choose from the following:  \n"

                    " 1 for scissor \n"

                    " 2 for rock \n"

                    " 3 for paper. \n")

#validate input so user only enters 1, 2, or 3

while user_choice != '1' and user_choice != '2' and user_choice != '3':

    user_choice = input("Please enter only '1' for scissor, '2' for rock, or '3' for paper: ")

#convert input to int

int_user_choice = int(user_choice)

Answer 4

获得输入后，您可以检查两个输入是否都是有效数字并且它是否在有效范围内，如果两个条件之一不成立，请再次请求输入。

valid_choices = {1,2,3}

while not user_choice.isdigit() and not int(user_choice) in valid_choices:

   user_choice = input("Please enter only '1' for scissor, '2' for rock, or '3' for paper: ")

或更简单地说

valid_choices = {'1','2','3'}

while not user_choice in valid_choices:

  user_choice = input("Please enter only '1' for scissor, '2' for rock, or '3' for paper: ")