14. Harmonic minor scales

The 12 notes within each octave is represented in the Python list called keys, as in the last example.

We list the semitone intervals of a minor scale, inside the minor list. We copy it to harmonic_minor list and then set the last two values, either raise or decrease by a semitone.

Inside the main loop, iterated over all keys, we use i%7 (i modulo 7) as index into harmonic_minor so we only access indexes 0 through 6.

Also we print a new line only if i is 7. The default end, for a print statement, is new line, unless we override it.

# mus14.py
# harmonic minor scales

import music21 as m21

minor = [2,1,2,2,1,2,2]
harmonic_minor = minor[:]
harmonic_minor[-2] += 1
harmonic_minor[-1] -= 1
print('harmonic minor = ',harmonic_minor)

keys = ['C','C#','D','D#',
        'E','F','F#','G',
        'G#','A','A#','B']

print('The 12 harmonic minor scales:')
for key in keys:
    n = m21.note.Note(key)
    midi = n.pitch.midi
    for i in range(8):
        n = m21.note.Note(midi = midi)
        if i<7: print(n.name, end= ' - ')
        else: print(n.name)
        midi = n.pitch.midi
        midi += harmonic_minor[i%7]

This will generate this output:

harmonic minor =  [2, 1, 2, 2, 1, 3, 1]
The 12 harmonic minor scales:
C - D - E- - F - G - G# - B - C
C# - E- - E - F# - G# - A - C - C#
D - E - F - G - A - B- - C# - D
E- - F - F# - G# - B- - B - D - E-
E - F# - G - A - B - C - E- - E
F - G - G# - B- - C - C# - E - F
F# - G# - A - B - C# - D - F - F#
G - A - B- - C - D - E- - F# - G
G# - B- - B - C# - E- - E - G - G#
A - B - C - D - E - F - G# - A
B- - C - C# - E- - F - F# - A - B-
B - C# - D - E - F# - G - B- - B