intersection, union, difference, symmetric difference for dictionaries

Tue Feb 25 17:21:05 EST 2014

Tim Chase <python.list at tim.thechases.com> wrote:
> a_dict = dict(...)
> b_dict = dict(...)
> a_set = set(a_dict)
> b_set = set(b_dict)
> added_keys = b_set - a_set
> removed_keys = a_set - b_set
> same_keys = a_set & b_set
> diff_keys = a_set ^ b_set
> all_keys = a_set | b_set
>> It would save some space if I didn't have to duplicate all the keys
> into sets (on the order of 10-100k small strings), instead being able
> to directly perform the set-ops on the dicts. But otherwise, it was
> pretty readable & straight-forward.
>It doesn't matter whether they were small strings or full-length novels, 
creating a set from a dict doesn't duplicate any strings.
-- 
Duncan Booth http://kupuguy.blogspot.com