Python: can generators be recursive?

Question

My recursive generator doesn't work:

def recursive_generator(list_):
    yield list_[0]
    recursive_generator(list_[1:])

for k in recursive_generator([6,3,9,1]):
    print(k)

Expected output:

6
3
9
1

Actual output:

6

How do I fix this? I'm trying to transfer the yield command to the stack level above in the recursion.

Answer 1

Try this:

def recursive_generator(lis):
    yield lis[0]
    yield from recursive_generator(lis[1:])

for k in recursive_generator([6,3,9,1]):
    print(k)

I should point out this doesn't work because of a bug in your function. It should probably include a check that lis isn't empty, as shown below:

def recursive_generator(lis):
    if lis:
        yield lis[0]
        yield from recursive_generator(lis[1:])

In case you are on Python 2.7 and don't have yield from, check this question out.