Python dicts are not ordered maps, they are dicts preserving insertion order.
Previously it was unpredictable, and that's why collections have OrderedDict; which makes sense instead of trusting an implementation detail of CPython from 3.6.
Is not mentioned in the docs: https://docs.python.org/3/library/stdtypes.html#mapping-type...
EDIT: but the behaviour is documented in OrderedDict itself! https://docs.python.org/3/library/collections.html?highlight...
Interesting!
You can get the first/last key of a 3.8 dict with dict.keys() and reversed(dict.keys()) which you can then delete to reimplement OrderedDict.popitem.
Deleting a key and reinserting it will let you reimplement move_to_end.
The only cool thing that OrderedDict's implementation might be useful for is to move to front (or anywhere else not the back) but it doesn't expose that api.
The difference is whether order is part of its identity. A dict is still just a set of pairs, not a list of them. It just happens that it also guarantees now that if you _iterate_ over the set you'll walk the keys in insertion order.
FWIW I don't think people agree on whether "element order is part of the value's identity" is part of the definition of "ordered map". There's plenty other languages & libs with ordered maps where the order isn't part of its identity but they still use the term "ordered map" in the name or the docs. Eg PHP's arrays or ImmutableJS's OrderedMap.