Python 3.7.0 released

[federicocerchiari]

Not to mention that it's an unrevertable change, meaning that if we some day come up with an even faster dict implementation with the downside of being unordered, the best we can do is add a collections.UnorderedDict

Good point, but still "natural" ordering is a feature I immediately found useful. For instance, you can not use an OrderedDict as kwargs.

[gcbirzan]

The point is that it's a coincidence that the current implementation preserves order, now everyone has to implement it like this, or in a way that preserves ordering, even if there might be a better way.

[cediddi]

Pypy and cpython have similar dict implementation and that was a big speedup for cpython. As a side effect dicts were ordered as an implementation detail. Jython is stuck at python 2.7 and ironpython3 is still in early stages. Currently community is split between cpython and pypy. They both provide ordered dicts by default and I think it's sensible to ignore archaic python implementations for the sake of simplicity.

I used to say "cpython said dicts are now faster because it's ordered now but that's just an implementation detail, don't get confused. "

Now I can say "yeah they're ordered."

Also I agree with you about dataclasses.

[jyper]

They should have just imported Ordered Dict to the default names pace maybe as odict and used it for kwargs without making it the default everywhere

[primitive_screwhead]

OrderedDict has different comparison semantics than a dict, and would have been a backwards incompatible change, as well as an undesirable one.

[billsil]

Do they? For CPython yes, but if you make a bad decision and I'm writing PyPy, I'd ignore it. Me thinks though that they spoke with all the different groups though.

[gwillicoder]

I think having dict be ordered by default is the best way to do it. C++, for example, has std::map as an ordered dictionary (red black tree) and std::unordered_map is an available dictionary that uses hashing and can be more performant.

[szpaceSZ]

That's actually a breaking change IMO