Python idiom to chain (flatten) an infinite iterable of finite iterables? [duplicate]

Answer 1

Use a generator:

(item for it in infinite for item in it)

The * construct unpacks into a tuple in order to pass the arguments, so there's no way to use it.

Answer 2

Starting with Python 2.6, you can use itertools.chain.from_iterable:

itertools.chain.from_iterable(iterables)

You can also do this with a nested generator comprehension:

def flatten(iterables):
    return (elem for iterable in iterables for elem in iterable)