While循环，比较多个值 [英] While loops, comparing more than one value

问题描述

仅将它与一件事进行比较，我就能理解如何完美地使用while循环，例如:

I can understand how to use the while loop perfectly if just to compare it with one thing, for example:

x=int(input("Guess my number 1-10"))
while x!=7: 
    print("Wrong!")
    x=int(input("Try again: "))
print("Correct it is 7. ")

但是，如果我想通过while循环比较两个或多个值(特别是如果我想验证某些东西)，我将执行以下操作:

However, if I want to compare two or more values through while loops (especially if I want to validate something), I would do something like this:

number=input("Would you like to eat 1. cake 2. chocolate 3. sweets: ")
while number!= "1" or number != "2" or number != "3":
    number=input("Please input a choice [1,2,3]")
#Some code...

当number等于1、2或3时，程序应该继续执行...但是无论我输入什么值，程序都不会继续执行，但是程序将停留在第2-3行的无限循环中.我也尝试过while number != "1" or "2" or "3"，同样也会发生无限循环.当我尝试用and替换所有or时，仅当number等于比较的第一个值(在本例中为"1")时，while循环才会中断.

When number does equal 1, 2 or 3, the program should proceed... but it doesn't, no matter what value I input, the program will be stuck at an infinite loop at line 2-3. I have also tried while number != "1" or "2" or "3" and the same infinite loops also occurs. When I try replacing all or with and, the while loop will only break when number equals the first value compared (which in this case is "1").

有什么办法可以解决这个问题?

Is there any way that I can resolve this?

推荐答案

如果条件为number != '1' or number != '2'，则这些条件之一将始终为true，因此它将永远不会中断.尝试使用while number not in ('1', '2', '3').

If you have a condition of number != '1' or number != '2', one of those conditions will always be true, so it'll never break out of the loop. Try while number not in ('1', '2', '3') instead.

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