Python-在！=中使用多个单词

Question

I want to use more than one word in !=, but I can't for the life of me understand or google my way how to. Can anyone help, and explain why I can't just do it like: != "No" != "no" !="n" !="N": etc etc

answers = ["Yes", "Not now not ever.", "Unclear answer, try again.", "Maybe.", "Probably not.", "Try again later.",
           "My sources says no.", "My sources says yes.", "Only when there is a full moon.", "It is certain.",
           "Cannot predict now.", "Outlook not so good", "Very doubtful.", "You may rely on it.",
           "Yes - definitely.", "As I see it, yes.", "Signs point to yes."]    

while str(input("Do you want to ask the Magic 8Ball a question?  Yes or No?  ")) != "No" != "no": # <-- problematic line
    str(input("Ask the mighty 8Ball your question:  "))
    randomanswer = answers[random.randint(0, len(answers) -1)]
    print("\n","The Magic 8Ball says: ")
    print(randomanswer, "\n")    
else:
    return

Answer 1

You can use a tuple of sentinel-values, eg

while foo not in ('No', 'no', 'N', 'n'):
    # code

or

while foo.lower() not in ('no', 'n'):
    # code

If there are a huge amount of sentinels, a set will perform faster than a tuple (for low amounts of values, hashing is not worth it).

You might also want to look into the re module for more sophisticated pattern matching.

Answer 2

尝试

while str(input("Do you want to ask the Magic 8Ball a question?  Yes or No?  ")) not in ["No", "no"]

Answer 3

You're looking for a way to chain together conditional statements . Unfortunately you cannot do it the way you're trying to do. However, you can use and and or to chain them together, which is how it's normally done. For example:

userinput = str(input("Do you want to ask the Magic 8Ball a question?  Yes or No?  "))

while userinput != "No" and userinput != "no":
    # have to get user input again at end of loop

But an even better approach is to find how to logically turn this into a single conditional, in this case using lower on the user input:

userinput = str(input("Do you want to ask the Magic 8Ball a question?  Yes or No?  "))
userinput = userinput.lower() # make it lowercase

while userinput != "no":
    # have to get user input again at end of loop

Finally, you can use random.choice to provide a random element from your answers array.

Answer 4

Change your problematic line to:

while input("Do you want to ask the Magic 8Ball a question?  Yes or No?  ").strip().lower() != "no":

This way, you convert the input string to lowercase ( lower() ) while also stripping any space the user might have typed in ( strip() )

Then, if user types: "No", lower() will convert it to all lowercase, "no" and then check it towards your != 'no' .

Anything typed into input() is a string, so can omit the str() .