razamatan

from random import shuffle, randrange

def randomize(iterable, bufsize=1000):
   ''' generator that randomizes an iterable. space: O(bufsize). time: O(n). '''
   buf = list()
   for x in iterable:
      if len(buf) == bufsize:
         i = randrange(bufsize)
         yield buf[i]
         buf[i] = x