Group each N elements of the iterable.

grouper.py

from itertools import zip_longest

# Group each `n` elements of the iterable, filling with `fillvalue` if needed.
#
#
# Sample usage:
#
#   >>> list(grouper([1, 2, 3, 4, 5, 6], 2))
#   [(1, 2), (3, 4), (5, 6)]
#
#   >>> list(grouper([1, 2, 3], 2))
#   [(1, 2), (3, None)]
#
#   >>> list(grouper([1, 2, 3], 2, fillvalue='fill value'))
#   [(1, 2), (3, 'fill value')]
#
def grouper(iterable, n, fillvalue=None):
    args = [iter(iterable)] * n
    return zip_longest(*args, fillvalue=fillvalue)