[Python-Dev] PEP 372 -- Adding an ordered directory to collections ready for pronouncement

Dennis Benzinger Dennis.Benzinger at gmx.net
Thu Mar 5 08:11:37 CET 2009

Hi Nick!

Am 04.03.2009 22:34, Nick Coghlan schrieb:
> Dennis Benzinger wrote:
>> I'd prefer encoding the order in the class name, therefore I suggest
>> (Ins|Insertion)(Order|Ordered)Dict, e.g. InsOrderDict. Abbreviating the
>> first group to simply I probably is too confusing because of the use of
>> I as a prefix for interfaces.
> Except I just don't see this proliferation of dict types with different
> sort orders ever happening.

Maybe there's a misunderstanding because I don't see it either. I was
trying to suggest four alternative names for the OrderedDict class. I
don't prefer encoding every possible sort order into the class name. I
just wanted to improve the name of OrderedDict.

> The distinction between OrderedDict and dict is that the order of
> keys()/values()/items() isn't arbitrary the way it is in a regular dict
> - there's a defined order that will always be used.

Yes, the insertion order.

> That's all the name
> tells you - if someone assumes they know what that ordering is without
> actually looking at the documentation (and gets it wrong as a result),
> then I don't see how that is any different from the fact that someone
> might mistakenly assume that list.sort() puts the items in descending
> order instead of ascending order.

And because that's all the name tells you I suggested to make the name
more clear by prepending Ins or Insertion.

> For other sort orders, it seems far more likely to me that a
> collections.SortedMap type would be added at some point in the future
> that accepts a key function like the one accepted by sorted() and
> list.sort(). Such a data type would make different trade-offs between
> insertion, deletion and lookup speeds than those made in the hash map
> based OrderedDict.
> [...]


Dennis Benzinger

More information about the Python-Dev mailing list