How to have nested generators continue their logic while parent generators needs to stop?

Question

Lets say I have the following code

def top():
    counter = 0

    for ch in child_1():
        print(ch)
        counter += 1

        if counter > 2:
            break


def child_1():
    for ch in child_2():
        yield ch

    print("child_1 logic has finished")


def child_2():
    for ch in "123456789":
        yield ch

    print("child_2 logic has finished")


if __name__ == '__main__':
    top()

Is there a way to have top() method to exit in the middle of the iteration like I have the counter condition, but let the children to finish their logic? (get to the code after the yield statement)

I tried to use while loop and other python tricks but it all went unsuccessful, I don't think there's a way without modifying the nested generators to not be a generators but I'm trying my shot here :D

Answer 1

If you want the children to "finish" what they're doing (i.e. perform the rest of the iteration), keep a reference to the iterator, and exhaust it after you break:

def top():
    counter = 0

    iter_1 = child_1()
    for ch in iter_1:
        print(ch)
        counter += 1

        if counter > 2:
            break

    for _ in iter_1:
        pass