Thanks, James! This is really helpful. : It would take a lot of coding to make that << work right. Better is the pythonic : : m[key] = [value] : : Its really only one more keystroke than : : m[key] << value
But it's only for the first element, right? I'd have to say meh[key1]...[keyN].append(elem2) after that, while I want an operator to look the same. Also, what's the shortest python idiom for get_or_set in expression? E.g., when creating a numeric leaf, I'd say if meh.has_key('a'): meh['a'] += 7 else: meh['a'] = 7 -- but I'd have to do it everywhere! That's why I'd like to override += to do the check/init for me. -- http://mail.python.org/mailman/listinfo/python-list