A gnarly little python loop

rusi rustompmody at gmail.com
Tue Nov 13 05:14:04 CET 2012


On Nov 12, 9:09 pm, Steve Howell <showel... at yahoo.com> wrote:
> On Nov 12, 7:21 am, rusi <rustompm... at gmail.com> wrote:
>
> > On Nov 12, 12:09 pm, rusi <rustompm... at gmail.com> wrote:> This is a classic problem -- structure clash of parallel loops
>
> > <rest snipped>
>
> > Sorry wrong solution :D
>
> > The fidgetiness is entirely due to python not allowing C-style loops
> > like these:
>
> > >> while ((c=getchar()!= EOF) { ... }
> > [...]
>
> There are actually three fidgety things going on:
>
>  1. The API is 1-based instead of 0-based.
>  2. You don't know the number of pages in advance.
>  3. You want to process tweets, not pages of tweets.
>
> Here's yet another take on the problem:
>
>     # wrap fidgety 1-based api
>     def search(i):
>         return api.GetSearch("foo", i+1)
>
>     paged_tweets = (search(i) for i in count())
>
>     # handle sentinel
>     paged_tweets = iter(paged_tweets.next, [])
>
>     # flatten pages
>     tweets = chain.from_iterable(paged_tweets)
>     for tweet in tweets:
>         process(tweet)

[Steve Howell]
Nice on the whole -- thanks
Could not the 1-based-ness be dealt with by using count(1)?
ie use
paged_tweets = (api.GetSearch("foo", i) for i in count(1))

{Peter]
> >>> while ((c=getchar()!= EOF) { ... }

for c in iter(getchar, EOF):
    ...

Thanks. Learnt something


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