I wasn't sure about the update method either, since AFAICT (not far) the values would in fact update, not append as I needed them to. But the iteritems and get combo definitely worked for me.
Thank you for the suggested link. I'm familiar with that page, but my skill level isn't so far along yet that I can more or less intuitively see how to combine methods, particularly in dictionaries. What would be a dream for me is if somebody just had tons of use-case examples - basically this post, condensed, for every potent combination of dictionary methods. A guy can dream. -- http://mail.python.org/mailman/listinfo/python-list
