Getting chromatic scale from diatonic scale (and also frequencies for all notes - with differences between flats and sharps).

chromatic_scale.py

"""From diatonic to chromatic. Also, flat and sharp notes.

Take notice that flats and sharps are not actually equal.
"""


diatonic = {
    'C': 264,
    'D': 297,
    'E': 330,
    'F': 352,
    'G': 396,
    'A': 440,
    'B': 495
}

flat = lambda x: round(x*15/16, 2)
sharp = lambda x: round(x*16/15, 2)

flats_and_sharps = dict(diatonic)

for note in diatonic.keys():
    sharp_note = sharp(diatonic[note])
    flat_note = flat(diatonic[note])

    flats_and_sharps['%sb' % note] = flat_note
    flats_and_sharps['%s#' % note] = sharp_note

flats_and_sharps = [(k, v) for (k, v) in flats_and_sharps.items()]
flats_and_sharps = sorted(flats_and_sharps, key=lambda x: x[1])

print('All flat (b) and sharp (#) notes:')
for (note, freq) in flats_and_sharps:
    print('%s %s' % (note.ljust(5), freq))

def is_allowed(note):
    return not (note.endswith('b') or note in ('E#', 'B#'))

chromatic = [note for (note, freq) in flats_and_sharps if is_allowed(note)]

print('\nChromatic scale:', ' '.join(chromatic))