stef.py

def find_chords(chords, music):
  """Search for chords within music (O(n) time).
  :param list chords: chords to look for, in order
  :param list music: music to search within
  """
    if len(music) < len(chords):
        return 0
    my_chord_i = -1
    occurrences = 0
    for my_chord in music:
        if my_chord in chords:
            j = chords.index(my_chord)
            if j > my_chord_i:
                my_chord_i = j
                if my_chord_i == len(chords) -1:
                    occurrences += 1
                    my_chord_i = -1
    return occurrences


if __name__ == '__main__':
    chords = ['C', 'F', 'G']

    music0 = ['C', 'F']
    times0 = find_chords(chords, music0)
    assert times0 == 0

    music1 = ['C', 'F', 'G']
    times1 = find_chords(chords, music1)
    assert times1 == 1

    music2 = ['C', 'F', 'G', 'A', 'C', 'F', 'G', 'E']
    times2 = find_chords(chords, music2)
    assert times2 == 2

    music3 = ['C', 'F', 'G', 'C', 'F', 'C', 'F', 'G', 'B', 'C', 'F', 'G']
    times3 = find_chords(chords, music3)
    assert times3 == 3

Thanks for this - it may actually come in good use later if I want to search specific chord progressions in the corpus. 👍