split_list_into_batches_comprehension.py

# It is an order of magnitude slower. So dont try this at home. I wanted to save
# it since I found this list comprehension interesting when I came up with it.

import itertools

def comprehend(long_list, batch_size):
    return [[u for u in k if u is not None] for k in
            itertools.izip_longest(*[long_list[i::batch_size]
                                     for i in range(batch_size)])]


def simple_split(long_list, batch_size):
    lists = []
    pointer = 0
    while pointer < len(long_list):
        lists.append(long_list[pointer:pointer + batch_size])
        pointer += batch_size
    return lists


# In  : %timeit simple_split(long_list, batch_size)
# Out : 10000 loops, best of 3: 56.8 µs per loop

# In  : %timeit comprehend(long_list, batch_size)
# Out : 1000 loops, best of 3: 432 µs per loop