On Fri, Dec 20, 2019 at 4:15 PM Wes Turner <wes.turner@gmail.com> wrote:
>
> How slow and space-inefficient would it be to just implement the set methods on top of dict?

Speed:  Dict doesn't cache the position of the first item.  Calling
next(iter(D)) repeatedly is O(N) in worst case.
Space:  It waste 8bytes per member.

>
> Do dicts lose insertion order when a key is deleted? AFAIU, OrderedDict do not lose insertion order on delete.

Dict keeps insertion order after deletion too.

>Would this limit the utility of an ordered set as a queue? What set methods does a queue need to have?

I want O(1) D.popleft(). (The name is borrowed from deque.  popfirst()
would be better maybe).

--
Inada Naoki  <songofacandy@gmail.com>