from struct import pack
from math import sin, pi

def au_file(name='out.au', freq=400, length=2, A=0.5):
	f = open(name, 'wb')
	f.write('.snd')
	f.write(pack('>5L', 24, -1, 2, 8000, 1))
	T = 8000./freq
	for i in range(length*8000):
		angle = 2*pi*i/T
		val = pack('b', A*sin(angle)*127)
		f.write(val)
	f.close()

from struct import pack
from math import pi, sin
import e32, audio 

def tone(freq=440, duration=1000, volume=0.5):
    f = open('D:\\out.au', 'wb')    # temp file
    f.write('.snd' + pack('>5L', 24, 8*duration, 2, 8000, 1))  #header
    for i in range(duration*8):
        sin_i = sin(i * 2*pi*freq/8000)  # sine wave
        f.write(pack('b', volume*127*sin_i))
    f.close()
    # now play the file
    s = audio.Sound.open('D:\\out.au')
    s.play()
    while s.state()==2: # playing
        e32.ao_yield()
    s.close()

>>> alist = [ '1', '1', '2', '1', '3', '4', '1', '3']
>>> [(a, alist.count(a)) for a in set(alist)]
[('1', 4), ('3', 2), ('2', 1), ('4', 1)]
>>> sorted(_, key=lambda x: -x[1])  # rank them
[('1', 4), ('3', 2), ('2', 1), ('4', 1)]

# from http://logic-users.org/forums/L-OT/295
# Each note's frequency is 2^(1/12) times of the previous note.

freq = 440 * 2^((n-69)/12)
n = 69 + 12*log(freq/440)/log(2)

# Doe, ray, me, fa, sol, la, tee, doe
>>> play([(i, 100) for i in [60, 62, 64,65, 67, 69, 71,72]])