Python generator to yield everything from another generator call

Question

I have a Python generator that can call itself to get more elements to yield. It looks like this:

def gen(list):
    # ...
    if list:
        for x in gen         


        

Answer 1

Python 3.3 added the yield from keyword. Here's a comparison between what you currently have and code using the new keyword:

yield_from_test.py:

def gen_for(a_list):
    if a_list:
        yield a_list[0]
        for x in gen_for(a_list[1:]):
            yield x

def gen_yield(a_list):
    if a_list:
        yield a_list[0]
        yield from gen_yield(a_list[1:])

if __name__ == '__main__':
    assert list(gen_for([1,2,3])) == list(gen_yield([1,2,3]))
    print(list(gen_yield([1,2,3])))

» python3 yield_from_test.py [1, 2, 3]