[Python-ideas] Introduce collections.Reiterable

[Neil Girdhar]

No, not things which are iterable but not iterators, things which are
*reiterable* rather than merely iterable.  That is, things that can be
iterated multiple times without the generated elements disappearing.


On Thu, Sep 19, 2013 at 5:20 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:

>
> On 19 Sep 2013 19:14, "Neil Girdhar" <mistersheik at gmail.com> wrote:
> >
> > I am proposing a new class "Reiterable" that is a subclass of Iterable.
>  For example, a dictionary view is a reiterable.  It would be fine to pass
> such an object to the function f.
>
> I'm afraid simply repeating your proposal still doesn't answer my
> question. You have indicated that you are trying to identify things that
> are iterable, but not iterators. That is already possible using a second
> isinstance check to exclude iterators.
>
> So, what is the value you see in adding a new ABC to further simplify an
> already simple check?
>
> Cheers,
> Nick.
>
> >
> > Best,
> > Neil
> >
> >
> > On Thu, Sep 19, 2013 at 5:12 AM, Nick Coghlan <ncoghlan at gmail.com>
> wrote:
> >>
> >>
> >> On 19 Sep 2013 18:59, "Neil Girdhar" <mistersheik at gmail.com> wrote:
> >> >
> >> > Well, generators are iterable, but if you write a function like:
> >> >
> >> > def f(s):
> >> >      for x in s:
> >> >              do_something(x)
> >> >      for x in s:
> >> >              do_something_else(x)
> >> >
> >> > x should not be a generator.  I am proposing adding a function to
> itertools like auto_reiterable that would take s and give you an reiterable
> in the most efficient way possible.
> >>
> >> Generators *are* iterators, though, so they fail the second half of the
> check. Hence my question - is there any obvious case where "iterable but
> not an iterator" gives the wrong answer?
> >>
> >> Cheers,
> >> Nick.
> >>
> >> >
> >> >
> >> > On Thu, Sep 19, 2013 at 4:32 AM, Nick Coghlan <ncoghlan at gmail.com>
> wrote:
> >> >>
> >> >> My question would be, does the new class add anything that isn't
> >> >
> >> >
> >> >
> >
> >
>
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