小编Eva*_*van的帖子

我正在寻求正确使用以下3个while循环的帮助:

while choice is None:  ...
while not isinstance (choice, int):  ...
while int(choice) not in range(0,1):  ...

也许这样的东西:

while choice is None and not isinstance (choice, int) and int(choice) not in range(0,1):
    print("Invalid option!")
    choice = input("Choose key: ")

我怎么能正确地嵌套这个？

choice = None
choice = input("Choose key: ")

while choice is None:
    choice = input("Choose key: ")

while not isinstance (choice, int):
    print("choice is an integer and I equal 0 or 1")
    print("Also if I am None or not …