On Wed, Jun 8, 2016 at 1:07 AM, Victor Stinner <victor.stin...@gmail.com> wrote: >> Abstract >> ======== >> >> This PEP changes the default class definition namespace to ``OrderedDict``. >> Furthermore, the order in which the attributes are defined in each class >> body will now be preserved in ``type.__definition_order__``. This allows >> introspection of the original definition order, e.g. by class decorators. >> >> Note: just to be clear, this PEP is *not* about changing ``__dict__`` for >> classes to ``OrderedDict``. > > What is the cost in term of performance?
Do you mean the cost of the PEP? The extra cost is negligible: creating an OrderedDict + mutation operations on it. Note that it is only used during class definition (execution of the class body). > > What can be slower: define a new class and/or instanciate a class? By "instantiate" do you mean the equivalent of "type(...)" or do you mean creating a new instance of a class? As noted above, the impact of using OrderedDict during class definition is negligible. During definition the cost of other operations will usually dwarf any extra overhead from using an OrderedDict. -eric _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
