1  
   2  from struct import pack
   3  from math import sin, pi
   4  
   5  def au_file(name='out.au', freq=400, length=2, A=0.5):
   6  	f = open(name, 'wb')
   7  	f.write('.snd')
   8  	f.write(pack('>5L', 24, -1, 2, 8000, 1))
   9  	T = 8000./freq
  10  	for i in range(length*8000):
  11  		angle = 2*pi*i/T
  12  		val = pack('b', A*sin(angle)*127)
  13  		f.write(val)
  14  	f.close()

   1  
   2  from struct import pack
   3  from math import pi, sin
   4  import e32, audio 
   5  
   6  def tone(freq=440, duration=1000, volume=0.5):
   7      f = open('D:\\out.au', 'wb')    # temp file
   8      f.write('.snd' + pack('>5L', 24, 8*duration, 2, 8000, 1))  #header
   9      for i in range(duration*8):
  10          sin_i = sin(i * 2*pi*freq/8000)  # sine wave
  11          f.write(pack('b', volume*127*sin_i))
  12      f.close()
  13      # now play the file
  14      s = audio.Sound.open('D:\\out.au')
  15      s.play()
  16      while s.state()==2: # playing
  17          e32.ao_yield()
  18      s.close()

   1  
   2  >>> alist = [ '1', '1', '2', '1', '3', '4', '1', '3']
   3  >>> [(a, alist.count(a)) for a in set(alist)]
   4  [('1', 4), ('3', 2), ('2', 1), ('4', 1)]
   5  >>> sorted(_, key=lambda x: -x[1])  # rank them
   6  [('1', 4), ('3', 2), ('2', 1), ('4', 1)]

   1  
   2  # from http://logic-users.org/forums/L-OT/295
   3  # Each note's frequency is 2^(1/12) times of the previous note.
   4  
   5  freq = 440 * 2^((n-69)/12)
   6  n = 69 + 12*log(freq/440)/log(2)
   7  
   8  # Doe, ray, me, fa, sol, la, tee, doe
   9  >>> play([(i, 100) for i in [60, 62, 64,65, 67, 69, 71,72]])