[Python-Dev] [Python-ideas] itertools.chunks(iterable, size, fill=None)

[Stefan Behnel]

anatoly techtonik, 04.07.2012 11:57:
> On Fri, Jun 29, 2012 at 11:32 PM, Georg Brandl wrote:
>> On 26.06.2012 10:03, anatoly techtonik wrote:
>>> Now that Python 3 is all about iterators (which is a user killer
>>> feature for Python according to StackOverflow -
>>> http://stackoverflow.com/questions/tagged/python) would it be nice to
>>> introduce more first class functions to work with them? One function
>>> to be exact to split string into chunks.
>>>
>>>      itertools.chunks(iterable, size, fill=None)
>>>
>>> Which is the 33th most voted Python question on SO -
>>>
>>> http://stackoverflow.com/questions/312443/how-do-you-split-a-list-into-evenly-sized-chunks-in-python/312464
>>>
>>> P.S. CC'ing to python-dev@ to notify about the thread in python-ideas.
>>>
>>
>> Anatoly, so far there were no negative votes -- would you care to go
>> another step and propose a patch?
> 
> Was about to say "no problem", but in fact - there is. Sorry from
> whining from my side and thanks for nudging. The only thought that a
> simple task of copy/pasting relevant code from
> http://docs.python.org/library/itertools.html?highlight=itertools#recipes
> will require a few hours waiting of download (still not everybody has
> a high-speed internet) makes me switch to other less time consuming
> tasks before getting around to it. These tasks become more important
> in a few hours, and basically I've passed through this many times
> before. It then becomes quite hard to switch back.
> 
> I absolutely don't mind someone else being credited for the idea,
> because ideas usually worthless without implementation. It will be
> interesting to design how the process could work in a separate thread.
> For now the best thing I can do (I don't risk even to mention anything
> with 3.3) is to copy/paste code from the docs here:
> 
> from itertools import izip_longest
> def chunks(iterable, size, fill=None):
>     """Split an iterable into blocks of fixed-length"""
>     # chunks('ABCDEFG', 3, 'x') --> ABC DEF Gxx
>     args = [iter(iterable)] * size
>     return izip_longest(fillvalue=fill, *args)

I think Raymond's change fixes this issue quite nicely, no need to touch at
the module code.

Stefan