Python does not skip "if [strg] or [strg] in variable"

Question

I'm writing a simple text-based game in Python 2.7. In the code below, even if the user answers something completely different than "run" or "nothing," the arrested() function still kicks in. I'm pretty sure the problem is in this line of code:

if "run" or "nothing" in answer:

because if I only provide one string, as follows:

if "run" in answer:

the program runs beautifully, calling remote_spot() if the answer does not contain "run". The whole code is the following:

def facing_cops():
    print "There are several cars that might serve as stake-outs for the cops. What do you do?"
    answer = raw_input("> ")
    if "run" or "nothing" in answer:
        arrested("Cops got suspicious. You are arrested, along with the drug dealer.")
    else:
        remote_spot()

What do you think is the matter?

Thanks,

Chris

score 3 · Answer 1 · answered Mar 21 '15 at 11:20

3

The or does not do what you want it to do. What you wrote is the same as:

if "run" or ("nothing" in answer):

"run" is a string and in a boolean context it is understood as True. So you want:

if "run" in answer or "nothing" in answer:

answered Mar 21 '15 at 11:20

syntonym

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Works like a charm! Thanks! I'd vote your answer up but I do not seem to have the reputation required to do so. – Chris Mar 21 '15 at 11:46
You can accept an answer that solved your problem. – syntonym Mar 21 '15 at 12:06
How do I do that? :) – Chris Mar 21 '15 at 12:38

score 2 · Accepted Answer · answered Mar 21 '15 at 11:24

2

The operator 'in' has priority over 'or' so that you're effectively testing if "run" or ("nothing" in answer). If you only have two, you can well write:

if "run" in answer or "nothing" in answer:

If ever you have more keywords to test than 2, things get a bit long to write and you could go for this option:

keywords = ["run","nothing","otherkeyword"]
if any(keyword in answer for keyword in keywords):

answered Mar 21 '15 at 11:24

vermillon

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Works like a charm! Thanks! I'd vote your answer up but I do not seem to have the reputation required to do so. – Chris Mar 21 '15 at 11:46
Just mark the answer as accepted, it will do :) – vermillon Mar 21 '15 at 15:40

Python does not skip "if [strg] or [strg] in variable"

2 Answers2