Iteration over list slices

gistfile1.py

from itertools import chain, islice

def divide(sequence, size):
  """
  >>> [i for i in divide(range(10), 3)]
  [[0, 1, 2], [3, 4, 5], [6, 7, 8], [9]]
  >>> [i for i in divide('ABCDEFGHIJKLMNOPQRSTUVWXYZ', 3)]
  ['ABC', 'DEF', 'GHI', 'JKL', 'MNO', 'PQR', 'STU', 'VWX', 'YZ']
  """
  i = 0
  while sequence[i:i+1]:
    yield sequence[i:i+size]
    i += size

def idivide(iterable, size):
  """
  >>> [list(i) for i in idivide(iter(xrange(10)), 3)]
  [[0, 1, 2], [3, 4, 5], [6, 7, 8], [9]]
  >>> ["".join(list(i)) for i in idivide(iter('ABCDEFGHIJKLMNOPQRSTUVWXYZ'), 3)]
  ['ABC', 'DEF', 'GHI', 'JKL', 'MNO', 'PQR', 'STU', 'VWX', 'YZ']
  """
  while True:
    yield chain([iterable.next()], islice(iterable, size-1))