Python wrapping around on a list when list index is out of range
I'm looking for some code improvement, or a pre-built version of what I've implemented myself as I think there might be, or should be, a cleaner way to achieve what I want.
I'm writing a piece of software to convert guitar tabs into classical notation, I need to convert the number on a tab to it's corresponding note and it would be useful for building a list of each strings note from the starting string.
I have a list of notes, (a - g#) and a list of frets (0, 21).
notes[fret] works fine for the first eleven notes but after that I obviously get an out of index error.
The code I have to get around this is here:
notes = ["a", "a#", "b", "c", "c#", "d", "e", "f", "f#", "g", "g#"] note = 21 while note >= len(notes): note -= 11 try: print notes[note] except: continue
It works but it seems a little... long, is there a better way to do this?
Use the % operator to produce a modulus:
notes[note % len(notes)]
>>> notes = ["a", "a#", "b", "c", "c#", "d", "e", "f", "f#", "g", "g#"] >>> note = 21 >>> notes[note % len(notes)] 'g#'
or in a loop:
>>> for note in range(22): ... print notes[note % len(notes)], ... a a# b c c# d e f f# g g# a a# b c c# d e f f# g g#