[Python-Dev] Compact ordered set
solipsis at pitrou.net
Thu Feb 28 06:56:55 EST 2019
On Thu, 28 Feb 2019 22:43:04 +1100
Steven D'Aprano <steve at pearwood.info> wrote:
> On Wed, Feb 27, 2019 at 02:15:53PM -0800, Barry Warsaw wrote:
> > I’m just relaying a data point. Some Python folks I’ve worked with do
> > make the connection between dicts and sets, and have questions about
> > the ordering guarantees of then (and how they relate).
> Sets and dicts are not related by inheritence (except that they're both
> subclasses of ``object``, but so is everything else). They don't share
> an implementation. They don't provide the same API. They don't do the
> same thing, except in the most general sense that they are both
> What connection are these folks making?
Some of them may be coming from C++, where the respective
characteristics of set and map (or unordered_set and
unordered_multimap) are closely related. I'm sure other languages
show similar analogies.
On a more abstract level, set and dict are both content-addressed
collections parametered on hash and equality functions. For
algorithmically-minded people it makes sense to see a close connection
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