On Sun, Jan 24, 2021 at 8:49 AM Cameron Simpson <c...@cskk.id.au> wrote:
>
> On 23Jan2021 12:20, Avi Gross <avigr...@verizon.net> wrote:
> >I am wondering how hard it would be to let some generators be resettable?
> >
> >I mean if you have a generator with initial conditions that change as it
> >progresses, could it cache away those initial conditions and upon some
> >signal, simply reset them? Objects of many kinds can be set up with say a
> >reinit() method.
>
> On reflection I'd do this with a class:
>
> class G:
> def __init__(self, length):
> self.length = length
> self.pos = 0
>
> def __next__(self):
> pos = self.pos
> if pos >= length:
> raise StopIteration()
> self.pos += 1
> return pos
>
> def __iter__(self):
> return self
>
Yep, or more conveniently:
class G:
def __init__(self, length):
self.length = length
self.pos = 0
def __iter__(self):
while self.pos < self.length:
yield self.pos
self.pos += 1
The only significant part is the fact that your generator function has
*external* state, which is what allows you to manipulate it. Generator
functions are still way cleaner for most purposes than handwritten
iterator classes.
ChrisA
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