I'm working with the 1850 O'Neills Folksong corpus, as it comes on music21 corpus. I need to iterate over all the songs.
I tried using the following code
songs = corpus.getComposer('oneills1850')
for ruta in songs:
op = converter.parse(ruta)
numbers = op.getNumbers()
...and then iterate on numbers. In most cases, each op variable is a Opus object, and each of its numbers is associated to a Score.
The problem is that this is not always true. For example, the 15th element of songs (i.e. index 14) is a Score object itself, not Opus. So my code crashes when attemping to use getNumbers.
The solucion, I guess, should be checking beforehand if op is an Opus (and in that case use getNumbers as I done before) or a Score (and in that case skipping that second iteration part). But I can't find how to do that, or any other thing that solves my problem.
If you have to be sure of the type of an object before calling methods on it, use isinstance:
if isinstance(op,Opus):