Erik <pyt...@lucidity.plus.com> writes: > On 29/04/17 23:40, Ned Batchelder wrote: > > For creating your own class that acts like a dict, you should derive > > from collections.abc.MutableMapping, which only requires > > implementing __getitem__, __setitem__, __delitem__, __iter__, and > > __len__. > > Or, I could derive from collections.OrderedDict and just implement the > two methods that I actually want to change the behavior of (did you > read the rest of my post?) ;)
Did you read Ned's? :-) You say that there are only two methods you want to change the behaviour of; but as you have found, those two methods are not the only ones you need to implement, in order to get the changed behaviour. > That's one of the points I'm trying to make - why is it harder than it > needs to be to do something this simple? The “needs” have already been expressed, by yourself and Ned: the type needs to provide fast performance. One cost of that, with the current implementation, is that you need to implement the MutableMapping protocol if you want a custom class. -- \ “Perchance you who pronounce my sentence are in greater fear | `\ than I who receive it.” —Giordano Bruno, burned at the stake by | _o__) the Catholic church for the heresy of heliocentrism, 1600-02-16 | Ben Finney -- https://mail.python.org/mailman/listinfo/python-list
