为什么它说响应没有定义，即使它是

Question

它一直告诉我响应没有定义。

while response not in Yes or No:
    response = input("Would you like to shut down the program?\nyes/no\n")
if response == "Yes":
    print("Goodbye.\n")
elif response == "No":
    print("Ok.")
    quit()
else: 
    print("I didn't understand that.\n")

Answer 1

假设在您提供的代码上方未引用它，则第一次通过循环时，未定义response 。 只有在第一次调用input()之后。 您需要在循环之前进行初始化。 类似response = None就足够了。

Answer 2

由于 Python 区分大小写，因此将响应转换为大写。

response.upper() == "是":

response.upper() == “否”：

response = input("Would you like to shut down the program?\nyes/no\n") 
if response.upper() == "YES":
     print("Goodbye.\n") 
elif response.upper() == "NO": 
     print("Ok.") 
     #quit() 
else: 
     print("I didn't understand that.\n")