__peter__ at web.de
Sun Jul 13 12:30:52 CEST 2008
Yosifov Pavel wrote:
> On 13 июл, 14:12, Peter Otten <__pete... at web.de> wrote:
>> Yosifov Pavel wrote:
>> > Whats is the way to clone "independent" iterator? I can't use tee(),
>> > because I don't know how many "independent" iterators I need. copy and
>> > deepcopy doesn't work...
>> There is no general way. For "short" sequences you can store the items in
>> a list which is also the worst-case behaviour of tee().
>> What are you trying to do?
> I try to generate iterators (iterator of iterators). Peter, you are
> right! Thank you. For example, it's possible to use something like
> def cloneiter( it ):
> """return (clonable,clone)"""
> return tee(it)
That is too abstract, sorry. What concrete problem are you trying to solve
with your cloned iterators? There might be a way to rearrange your setup in
a way that doesn't need them.
> But I think (I'm sure!) it's deficiency of Python iterators! They are
> not very good...
Well, I think Python's iterators, especially the generators, are beautiful.
More importantly, I think there is no general way to make iterators
copyable, regardless of the programming language. The problem is that most
of the useful ones depend on external state.
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