if else否则声明与字母（A，B，C或D）的问卷

Question

我需要帮助我的if / else语句用于哪个奇迹字符问卷如何添加＆＃34;而＃34;使python编码正确。谢谢。我想确保他们不能输入除A，B，C或OR之外的任何字母。

if str(input())) not ('A','B','C','D')
else ("ask them again");

Answer 1

一个简单的选项是检查每个字母：

choice='f'
while choice!='A' and choice!='B' and choice!='C' and choice!='D':
  choice=input('Enter letter')

如果您想在.upper()

之后立即使用input(..)进行检查

Answer 2

answer = ""
possibleAnswers = {"A","B","C","D"}

while answer not in possibleAnswers:
    answer = input("Select an answer:")