Can I memoize a Python generator?

Question

I have a function called runquery that makes calls to a database and then yields the rows, one by one. I wrote a memoize decorator (or more accurately, I just stole

Answer 1

I realise this is somewhat of an old question, but for those who want a full solution: here's one, based on jsbueno's suggestion:

from itertools import tee
from types import GeneratorType

Tee = tee([], 1)[0].__class__

def memoized(f):
    cache={}
    def ret(*args):
        if args not in cache:
            cache[args]=f(*args)
        if isinstance(cache[args], (GeneratorType, Tee)):
            # the original can't be used any more,
            # so we need to change the cache as well
            cache[args], r = tee(cache[args])
            return r
        return cache[args]
    return ret