On Jan 29, 2013 9:26 AM, "Oscar Benjamin" <oscar.j.benjamin@gmail.com> wrote:
>
> On 29 January 2013 11:51, yoav glazner <yoavglazner@gmail.com> wrote:
> > Here is very similar version that works (tested on python27)
> >>>> def stop():
> > next(iter([]))
> >
> >>>> list((i if i<50 else stop()) for i in range(100))
> > [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
> > 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
> > 40, 41, 42, 43, 44, 45, 46, 47, 48, 49]
>
> That's a great idea. You could also do:
> >>> list(i for i in range(100) if i<50 or stop())
>
> It's a shame it doesn't work for list/set/dict comprehensions, though.
>

I know I'm showing my ignorance here, but how are list/dict/set comprehensions and generator expressions implemented differently that one's for loop will catch a StopIteration and the others won't? Would it make sense to reimplement list/dict/set comprehensions as an equivalent generator expression passed to the appropriate constructor, and thereby allow the StopIteration trick to work for each of them as well?

Regards,

Zach Ware