split a generator/iterable every n items in python (splitEvery)

Question

I\'m trying to write the Haskel function \'splitEvery\' in Python. Here is it\'s definition:

splitEvery :: Int -> [e] -> [[e]]
    @\'splitEvery\' n@ s         


        

Answer 1

I came across this as I'm trying to chop up batches too, but doing it on a generator from a stream, so most of the solutions here aren't applicable, or don't work in python 3.

For people still stumbling upon this, here's a general solution using itertools:

from itertools import islice, chain

def iter_in_slices(iterator, size=None):
    while True:
        slice_iter = islice(iterator, size)
        # If no first object this is how StopIteration is triggered
        peek = next(slice_iter)
        # Put the first object back and return slice
        yield chain([peek], slice_iter)