A gnarly little python loop
__peter__ at web.de
Sun Nov 11 19:34:06 CET 2012
Steve Howell wrote:
> On Nov 11, 1:09 am, Paul Rubin <no.em... at nospam.invalid> wrote:
>> Cameron Simpson <c... at zip.com.au> writes:
>> > | I'd prefer the original code ten times over this inaccessible beast.
>> > Me too.
>> Me, I like the itertools version better. There's one chunk of data
>> that goes through a succession of transforms each of which
>> is very straightforward.
> Thanks, Paul.
> Even though I supplied the "inaccessible" itertools version, I can
> understand why folks find it inaccessible. As I said to the OP, there
> was nothing wrong with the original imperative approach; I was simply
> providing an alternative.
> It took me a while to appreciate itertools, but the metaphor that
> resonates with me is a Unix pipeline. It's just a metaphor, so folks
> shouldn't be too literal, but the idea here is this:
> page_nums -> pages -> valid_pages -> tweets
> The transforms are this:
> page_nums -> pages: call API via imap
> pages -> valid_pages: take while true
> valid_pages -> tweets: use chain.from_iterable to flatten results
> Here's the code again for context:
> def get_tweets(term):
> def get_page(page):
> return getSearch(term, page)
> page_nums = itertools.count(1)
> pages = itertools.imap(get_page, page_nums)
> valid_pages = itertools.takewhile(bool, pages)
> tweets = itertools.chain.from_iterable(valid_pages)
> return tweets
Actually you supplied the "accessible" itertools version. For reference,
here's the inaccessible version:
"""Twitter search API mock-up"""
pages = [
["a", "b", "c"],
def GetSearch(term, page):
assert term == "foo"
assert page >= 1
if page > len(api.pages):
from collections import deque
from functools import partial
from itertools import chain, count, imap, takewhile
term = "foo"
takewhile(bool, imap(partial(api.GetSearch, term), count(1))))),
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