Add script calculate Major scale

Python/major_scale.py

@@ -0,0 +1,45 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Author: [email protected]
+# Tested with Python3
+# python major_scale.py C
+# ['C', 'D', 'E', 'F', 'G', 'A', 'B', 'C']
+
+import argparse
+
+__doc__ = '''Script prints out major scale start from input note.'''
+
+notes = ('A', 'Bb', 'B', 'C', 'Db', 'D', 'Eb', 'E', 'F', 'Gb', 'G', 'Ab')
+noteno = len(notes)
+WHOLE = 2
+HALF = 1
+
+
+def next_steps(note, steps=HALF):
+    idx = notes.index(note)
+    for step in range(steps):
+        idx = (idx + 1) % noteno
+    return notes[idx]
+
+
+def major_scale(start):
+    out = []
+    out.append(start)
+    n = start
+    for step in [WHOLE, WHOLE, HALF, WHOLE, WHOLE, WHOLE, HALF]:
+        n = next_steps(n, step)
+        out.append(n)
+
+    return out
+
+
+def main():
+    argp = argparse.ArgumentParser()
+    argp.add_argument('note', help='Note starts the major scale')
+    args = argp.parse_args()
+    print(major_scale(args.note))
+
+
+if __name__ == "__main__":
+    main()