Itertools wishlists

[Raymond Hettinger]

>     Steven> complex atomicity test).  I also have the feeling that any
>     Steven> complicated atomictiy test is more than a simple and-ing
>     Steven> of several tests...

"Ville Vainio"
> I also have the feeling that if the atomicity criterion was any more
> complex in the API, the proposal would be shot down immediately on the
> grounds of not being fundamental enough as concept.

Would this meet your needs?

def flatten(iterable, atomic_iterable_types=(basestring,)):
    iterstack = [iter(iterable)]
    while iterstack:
        for elem in iterstack[-1]:
            if not isinstance(elem, atomic_iterable_types):
                try:
                    it = iter(elem)
                except TypeError:
                    pass
                else:
                    iterstack.append(it)
                    break
            yield elem
        else:
            iterstack.pop() # only remove iterator when it is exhausted


Raymond Hettinger