验证python中的输入

Question

我正在尝试编写一个石头剪刀布程序，其中的选择是 1、2 和 3。我想验证输入，以便除了这三个选择之外的任何输入都将打印一条消息，说明输入有效，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 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 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

如果您想稍后将其与整数进行比较，则需要将输入从字符串转换为整数。 如果您想避免一遍又一遍地重复逻辑，您可以使用列表。

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

获得输入后，您可以检查输入是否都是有效数字且是否在有效范围内，如果两个条件之一不成立，则再次请求输入。

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: ")

或者更简单

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: ")

Answer 3

在一个循环中完成整个提示/验证。 在满足条件之前，用户不能继续

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 4

你的不正确，因为输入返回的是字符串类型，而你正在检查类型是 int，所以在循环中更改类型。 此外，您不能使用or如果您希望它在其中一种情况为真时终止，在这种情况下，您必须使用and 。

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)