prize17-8, Exercise 2: E Dorian and G Dorian

notes = ["C", "Db", "D", "Eb", "E", "F", "Gb", "G", "Ab", "A", "Bb", "B"]
steps = [2, 1, 2, 2, 2, 1, 2]
def dorian(root):
    i = notes.index(root)
    scale = [root]
    for s in steps[:-1]:
        i = (i + s) % 12
        scale.append(notes[i])
    return scale
print("E Dorian :", dorian("E"))
print("G Dorian :", dorian("G"))

Output (run and checked):

E Dorian : ['E', 'Gb', 'G', 'A', 'B', 'Db', 'D']
G Dorian : ['G', 'A', 'Bb', 'C', 'D', 'E', 'F']

What you notice: the program only has flat names, so F-sharp appears as Gb and C-sharp as Db. In standard notation E Dorian is written E, F-sharp, G, A, B, C-sharp, D, and the notes are the same pitches under different names.

Care: a program that spells every black key as a flat gives correct pitches but not always correct spelling.