On Mon, Nov 27, 2017 at 3:55 PM, Steven D'Aprano <st...@pearwood.info> wrote:
> On Mon, Nov 27, 2017 at 12:17:31PM +0300, Kirill Balunov wrote: > > > > 2. Should this work only for generators or for any iterators? > > I don't understand why you are even considering singling out *only* > generators. A generator is a particular implementation of an iterator. I > can write: > > def gen(): > yield 1; yield 2; yield 3 > > it = gen() > > or I can write: > > it = iter([1, 2, 3]) > > and the behaviour of `it` should be identical. > > > I can see where this is coming from, but I wrote about it in a new thread: "generator vs iterator etc. (was: How assignment should work with generators?)". > > But maybe we should consider allowing slice notation on arbitrary > iterators: > > x, y = it[:2] > > > I have not thought this through in any serious detail, but it seems to > me that if the only problem here is the inconvenience of using islice(), > we could add slicing to iterators. I think that would be better than > having iterators and other iterables behave differently. > > Making iterators behave like sequences (slicing etc.) introduces various issues including memory considerations and backwards compatibility. That's why the `views` package [1] keeps a clear separations between sequences and iterators. IterABLES are a bit fuzzy here, but they at least should be able to produce an iterator. I should have time to discuss this more at a later point, if needed. —Koos [1] https://github.com/k7hoven/views -- + Koos Zevenhoven + http://twitter.com/k7hoven +
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