Aguy Aguy - 4 months ago 13
Python Question

Can generators be recursive?

I naively tried to create a recursive generator. Didn't work. This is what I did:

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

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


All I got was the first item
6
.

Is there a way to make such code work? Essentially transferring the
yield
command to the level above in a recursion scheme?

Answer

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.

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.

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