Returning every element from a list (Python)

There is a yield statement which matches perfectly for this usecase.

def foo(a):
    for b in a:
        yield b

This will return a generator which you can iterate.

print [b for b in foo([[a, b], [c, d], [e, f]])

When a python function executes:

return a, b, c

what it actually returns is the tuple (a, b, c), and tuples are unpacked on assignment, so you can say:

x, y, z = f()

and all is well. So if you have a list

mylist = [4, "g", [1, 7], 9]

Your function can simply:

return tuple(mylist)

and behave like you expect:

num1, str1, lst1, num2 = f()

will do the assignments as you expect.

If what you really want is for a function to return an indeterminate number of things as a sequence that you can iterate over, then you'll want to make it a generator using yield, but that's a different ball of wax.