Question

For learning purposes, I’m trying to make a function using Python that takes in another function and two arrays as parameters and calls the function parameter on each index of each array parameter. So this should call add on a1[0] & a2[0], a1[1] & a2[1], etc. But all I’m getting back is a generator object. What’s wrong?

def add(a,b):
    yield a + b


def generator(add,a1,a2):
    for i in range(len(a1)):
        yield add(a1[i],a2[i])


g = generator(add,a1,a2)

print g.next()

I’ve also tried replacing what I have for yield above with

yield map(add,a1[i],a2[i])

But that works even less. I get this:

TypeError: argument 2 to map() must support iteration

Answer 1

Your definition of add() is at least strange (I’m leaning twoards calling it “wrong”). You should return the result, not yield it:

def add(a, b):
    return a + b

Now, your generator() will work, though

map(add, a1, a2)

is an easier and faster way to do (almost) the same thing. (If you want an iterator rather than a list, use itertools.imap() instead of map().)