On Oct 13, 2019, at 19:15, Steve Jorgensen <ste...@stevej.name> wrote: > > What if, instead, there was an `OrderedBag` class that acts like a `list` and > supports set operations. > > The advantage of this is that any hidden indexing that is used to optimize > the operations could be efficiently created in the object that results from > the set operation during its construction while performing the operation. > Using lists, any such indexes would have to be produced and discarded for > each operation (or could perhaps be kept in weak references or something like > that, but that's messy).
This sounds doable, but nontrivial to design and implement, and with a lot of tradeoffs to consider. I’m not sure there is a one-size-fits-all implementation that would be good enough for most uses, but if there is, you probably need to find it and at least give us a proof of concept. For example, when I’ve needed to do the kind of thing you seem to be talking about, it’s often because I have a (multi)set of values with different orderings on it. Like a database table with multiple indices. If you don’t have any ordering except for a partial ordering on hash/equality, you probably wouldn’t want the same thing I do. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/LQK7THRK75DQGJNTWIEWCJVMRSXGY2GJ/ Code of Conduct: http://python.org/psf/codeofconduct/
