[Python-Dev] Iterator addition?

[Moshe Zadka]

On Mon, 30 Jul 2001, Sami Hangaslammi <shang@cc.jyu.fi> wrote:

> Since iterator objects work like sequences in several contexts, maybe they
> could support sequence-like operations such as addition. This would let
> you write
> 
>   for x in iter1 + iter2:
>       do_something(x)
> 
> instead of
> 
>   for x in iter1:
>       do_something(x)
> 
>   for x in iter2:
>       do_something(x)
> 
> or the slightly better
> 
>   for i in iter1,iter2:
>       for x in i:
>           do_something(x)

No, instead of:


class concat:

    def __init__(self, *iterators):
        self.iterators = list(iterators)

    def __iter__(self): return self

    def next(self):
        while self.iterators:
            try:
                return self.iterators[0].next() 
            except StopIteration:
                del self.iterators[0]
        else:
            raise StopIteration


for x in concat(iter1, iter2):
    do_something(x)

(Note that the first n-2 lines can be refactored. Wasn't there talk
about having an iterator module with useful stuff like that?)

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