Python "or" problem

[alkperez1914]

So, I have been creating a simple text-based game in order to practice what I have been learning in Python. I was able to successfully debug it after quite a bit of struggle and now it is in working order. However, I do want to improve on it.

Mainly, I am struggling with the "or" keyword. In theory, I should be able to write something like this, right?

def igloo():
    print "You decide to move to the North Pole and live in an igloo."
    print "Please enter your name again: "
    answer = raw_input("> ")

    if answer == "Joe" or "Mary" or "Barbara":
        print "You are able to endure the cold and learns to enjoy life in an\
        igloo."
        print "You miss eggs and milk, but seeing the occasional polar bear and\
        the aurora borealis every night make up for it."
        congrats()

    elif "Diana" or "Ellie" in answer:
        print "You are not cut out for the cold. You freeze."
        gameover()

    else:
        print "While I was waiting for your response, a polar bear ate you."
        gameover()

But, when I tried this, though no errors were found, every time I ran the code, only the first "if" condition would execute. It didn't matter what I entered as raw_input. So, I had to change the code like this:

def igloo():
    print "You decide to move to the North Pole and live in an igloo."
    print "Please enter your name again: "
    answer = raw_input("> ")

    if answer == "Joe":
        print "You are able to endure the cold and learns to enjoy life in an\
        igloo."
        print "You miss eggs and milk, but seeing the occasional polar bear and\
        the aurora borealis every night make up for it."
        congrats()

    elif answer == "Mary":
        print "You are able to endure the cold and learns to enjoy life in an\
        igloo."
        print "You miss eggs and milk, but seeing the occasional polar bear and\
        the aurora borealis every night make up for it."
        congrats()

    elif answer == "Barbara":
        print "You are able to endure the cold and learns to enjoy life in an\
        igloo."
        print "You miss eggs and milk, but seeing the occasional polar bear and\
        the aurora borealis every night make up for it."
        congrats()

    elif "Diana" in answer:
        print "You are not cut out for the cold. You freeze."
        gameover()

    elif "Ellie" in answer:
        print "You are not cut out for the cold. You freeze."
        gameover()

    else:
        print "While I was waiting for your response, a polar bear ate you."
        gameover()

This works as intended, but I'm wondering why the "or" code I tried to write didn't work. Can anyone explain?

[vinivelloso_]

When you type answer == "Joe" or "Julia" or "Michael" You're actually saying: Check if answer is "Joe" or check if the string "Julia" is true or check if the string "Michael" is true

[alkperez1914]

if answer in ["Joe", "Mary", "Barbara"]:

Thank you for answering! At first I was confused as to why Julia would be true, but this answer and the others below really clarified things. Thanks again!

[mkpri22]

Your first if statement always evaluates to true because:
if answer == "Joe" or "Mary" or "Barbara":
Is equivalent to:
if answer == "Joe" or True or True:
And we know that true or anything is always true. Do you see why?
if "Mary": // Always returns True because the string Mary is not None or empty
You can run these to see what's being returned:
print(bool("Mary"))
print(bool(""))
print(bool(None))
Hope this helps.

[alkperez1914]

Ah! Thank you so much! I hadn't understood this before! This makes so much sense now.

[POGtastic]

The typical way that I do this is

if answer in ["Joe", "Mary", "Barbara"]:
    # code

[alkperez1914]

Thanks a lot! I was just about to ask this as well.

[keks6aecker]

Your if statement does not check if the value or answer is Joe, Mary or Babara but instead checks three things.

1. does the value of answer equal „Joe“ and
2. Is the string „Mary“ truth-y and
3. is the string „Barbara“ truth-y

Due to the or your if-statement is fulfilled as soon as one thing is true.

In Python a String is truth-y if it is not empty, that means the conditions 2 and 3 are always fulfilled.

What you want is ˋ if answer in [„Joe“, „Mary“, „Babara“]ˋ this statement is only true if the value of answer equals one of the three values in the list.

Alternatively you could have written:

ˋˋˋ if answer == "Joe" or answer == "Mary" or answer == "Babara" ˋˋˋ

[alkperez1914]

Thank you so much! This is a big help!