Thanks for posting this. I picked up a few useful hints; particularly I'd missed the rather handy enumerate function. Also, I'll be thinking more of using generators to flatten nested loops into a single loop.

I really like your format for blog slides. So much more useful than just the slides, maybe even a video.

To loop one has to have iterable in the first place whereas often we get scalar value instead. That's why I find it useful to have this kind of "adapter":

    def as_iterable(input,
                    scalar_types=(basestring,),
                    empty_types=(types.NoneType,)):
        if isinstance(input, empty_types):
            return ()
        else:
            if isinstance(input, scalar_types):
                return (input,)
            else:
                return iter(input)

Superb article/talk. Thanks.