Brilliant or insane code?

Insane, because it relies on the zip implementation detail. If you cared about a measly factor of 4 in performance you wouldn't be using python anyway.

Re: Brilliant or insane code?

#5

Post by signed0 » Sun, Sep 01, 2013, 11:35 AM UTC

It's not brilliant.

This accomplishes the same thing without being hard to understand:

    from itertools import islice

    iterator = iter(array)
    try:
        while True:
           yield list(islice(iterator, 3))
    except StopIteration:
        pass

Re: Brilliant or insane code?

#6

Post by StavrosK » Sun, Sep 01, 2013, 11:36 AM UTC

signed0 wrote: post #5

It's not brilliant. This accomplishes the same thing without being hard to understand: from itertools import islice iterator = iter(array) try: while True: yield list(islice(iterator, 3)) except StopIteration: pass

Sure, there are many ways to do it, but I think the author was going for speed here.

Re: Brilliant or insane code?

#7

Post by bjourne » Sun, Sep 01, 2013, 11:38 AM UTC

I think the code is pretty ok, except for the stupid name, docstring and that it is a method and not a free function.

    def chunks(seq, n):
        "groups the elements of the seq into a list of n-sized chunks."
        return zip(*[iter(seq)]*n)

Re: Brilliant or insane code?

#8

Post by mjburgess » Sun, Sep 01, 2013, 11:40 AM UTC

It does not rely on an implementation detail, that is how iterators work. He's just supplied the same iterator to a function which consumes iterators... that's exactly the expected behaviour.

Re: Brilliant or insane code?

#9

Post by hknozcan » Sun, Sep 01, 2013, 11:42 AM UTC

We all love short and fast. But this is definitely an interesting approach. I'd love to see similar approaches to problems if you guys can point out to some.

Re: Brilliant or insane code?

#10

Post by signed0 » Sun, Sep 01, 2013, 11:43 AM UTC

StavrosK wrote: post #6

signed0 wrote: post #5

It's not brilliant. This accomplishes the same thing without being hard to understand: from itertools import islice iterator = iter(array) try: while True: yield list(islice(iterator, 3)) except StopIteration: pass

Sure, there are many ways to do it, but I think the author was going for speed here.

I'd be surprised if my way is slower. Any time you unpack into a function such as zip() python has to create an intermediary list to store all the results before calling the function.