Else, elif, if problems in Python

Question

instrument=(raw_input("Which kind of tab would you like to view? Enter 'Guitar' or 'Bass' for a random tab " ))
print
if instrument=='guitar' or 'Guitar':
    print ("0-3-5---0-3-6-5---0-3-5-3-0")
elif instrument=='bass' or 'Bass':
    print ("3-5-12--12-0-5-6-0-0-0-3")
else:
    print 'Sorry, please re-enter a proper answer'

This code prints out the 'guitar' tab(the first if statement) every time, no matter what you type in for the variable 'instrument'.

I'm trying to teach myself python and am just jumping in and learning as I go, this is a basic program I'm working on and want to expand on.

I've looked online but from what I've read about if else statements, it looks to my novice eyes that this code should work. I'm missing something that I just can't figure out

unutbu · Accepted Answer · 2012-10-08 01:45:15Z

8

if instrument=='guitar' or 'Guitar':

is parsed like

if (instrument=='guitar') or ('Guitar'):

Non-empty strings like 'Guitar' are evaluated as True, so the first condition is always True.

Instead, use

if instrument in ('guitar', 'Guitar'):

or, if you are willing to accept funny spellings like 'gUiTAR', you could use

if instrument.lower() == 'guitar':

answered Oct 8, 2012 at 1:45

unutbu

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1 Comment

Amber Over a year ago

I think you mean ('guitar', 'Guitar').

Blender · Accepted Answer · 2012-10-08 01:56:43Z

7

instrument == 'guitar' or 'Guitar'

should be

instrument == 'guitar' or instrument == 'Guitar'

or better,

instrument in ('guitar', 'Guitar')

or even

instrument.lower() == 'guitar'

and the same for the bass portion.

The reason why it's always outputting the first option is that a == b or c...

...is actually read as (a == b) or c.

The or operator is not used how you think it is. It is a logical or, not a "multiple options" separator.

edited Oct 8, 2012 at 1:56

Blender

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answered Oct 8, 2012 at 1:44

Amber

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1 Comment

01110100 Over a year ago

That 'bible' variable actually should've been 'instrument', sorry I fixed it in my question. But your examples still stand true

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