驗證python中的輸入

Question

我正在嘗試編寫一個石頭剪刀布程序，其中的選擇是 1、2 和 3。我想驗證輸入，以便除了這三個選擇之外的任何輸入都將打印一條消息，說明輸入有效，並要求用戶重新輸入數據。 我有一些工作，但是，即使我輸入 1 2 或 3，它仍然會打印消息並要求更多輸入。

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

如果您想稍后將其與整數進行比較，則需要將輸入從字符串轉換為整數。 如果您想避免一遍又一遍地重復邏輯，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

獲得輸入后，您可以檢查輸入是否都是有效數字且是否在有效范圍內，如果兩個條件之一不成立，則再次請求輸入。

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: ")

或者更簡單

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

在一個循環中完成整個提示/驗證。 在滿足條件之前，用戶不能繼續

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

你的不正確，因為輸入返回的是字符串類型，而你正在檢查類型是 int，所以在循環中更改類型。 此外，您不能使用or如果您希望它在其中一種情況為真時終止，在這種情況下，您必須使用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)