python - Python“或”语句语法不起作用？

Question

我对python编程比较陌生，无论如何这是一大段代码的一小部分。这似乎导致了问题：

command = input("Command: ")

while command != ("Exit lift" or "Up" or "Down" or "1" or "2" or "3" or "Cycle"):
    print("Error: Command entered doesn't match the 'Commands' list, or isn't a possible command at this time! Please try again...")
    command = input("Command: ")

print ("Works")

基本上，我测试了这些命令，它只接受“Exit lift”命令，以及“Up”、“Down”、“1”...等。不会工作。

有什么建议么？初学者

Answer 1

("Exit lift" or "Up" or "Down" or "1" or "2" or "3" or "Cycle")被评估为'Exit lift'。

>>> ("Exit lift" or "Up" or "Down" or "1" or "2" or "3" or "Cycle")
'Exit lift'

所以command != ("Exit lift" or "Up" or "Down" or "1" or "2" or "3" or "Cycle"):等价于command != ("Exit lift")。

not in与序列一起使用：

while command not in ("Exit lift", "Up", "Down", "1", "2", "3", "Cycle"):
    ....

Answer 2

代替

while command != ("Exit lift" or "Up" or "Down" or "1" or "2" or "3" or "Cycle"):

你应该使用

while not command in ("Exit lift", "Up", "Down", "1", "2", "3", "Cycle"):

Answer 3

你可以使用一个数组，并使用这个in词

allowed = ["Exit lift", "Up", "Down", "1", "2", "3", "Cycle"]

while command not in allowed:
    print "not allowed!"

print "works"