What is the most "pythonic" way to iterate over a list in chunks?
def chunker(seq, size): return (seq[pos:pos + size] for pos in range(0, len(seq), size))# (in python 2 use xrange() instead of range() to avoid allocating a list)Works with any sequence:
text = "I am a very, very helpful text"for group in chunker(text, 7): print(repr(group),)# 'I am a ' 'very, v' 'ery hel' 'pful te' 'xt'print '|'.join(chunker(text, 10))# I am a ver|y, very he|lpful textanimals = ['cat', 'dog', 'rabbit', 'duck', 'bird', 'cow', 'gnu', 'fish']for group in chunker(animals, 3): print(group)# ['cat', 'dog', 'rabbit']# ['duck', 'bird', 'cow']# ['gnu', 'fish']
Modified from the Recipes section of Python's itertools docs:
from itertools import zip_longestdef grouper(iterable, n, fillvalue=None): args = [iter(iterable)] * n return zip_longest(*args, fillvalue=fillvalue)Example
grouper('ABCDEFG', 3, 'x') # --> 'ABC' 'DEF' 'Gxx'Note: on Python 2 use izip_longest instead of zip_longest.
chunk_size = 4for i in range(0, len(ints), chunk_size): chunk = ints[i:i+chunk_size] # process chunk of size <= chunk_size