Generators can only yield ints?

[bearophileHUGS at lycos.com]

defn noob:
> Any way to get around this?

Your code is wrong, this is one of the correct versions:

from itertools import izip

def letters():
    lower = xrange(ord('a'), ord('z')+1)
    upper = xrange(ord('A'), ord('Z')+1)
    for lc, uc in izip(lower, upper):
        yield chr(lc)
        yield chr(uc)

print list(letters())

There are other ways to do the same thing.

Bye,
bearophile