Are all objects in Python equality-comparable? I know that you can delete
__hash__ to make an object unhashable (e.g., dicts). If so, this is a
great addition.
On Saturday, July 4, 2020 at 5:26:45 PM UTC-4, Joao S. O. Bueno wrote:
>
>
>
> On Sat, 4 Jul 2020 at 16:51, Serhiy Storchaka <stor...@gmail.com
> <javascript:>> wrote:
>
>> 30.06.20 18:58, Joao S. O. Bueno пише:
>> > I ended up writting an __eq__ - and in the process I found it is not
>> > _that_ straightforward due
>> > to having to check subclasses types when comparing.
>> > (given Base sequence A, child class B(A), class C(A) and class B1(B) -
>> > Instances of B and B1 can be
>> > equal, but instances of B and C should always be different) - or in
>> > Python, inside __eq__ :
>> > if not issubclass(type(other), type(self)) and not
>> > issubclass(type(self), type(other)):
>> > return False
>>
>> It would be more correct to return NotImplemented.
>>
>> Also, it is enough to test isinstance(other, type(self)) because
>> other.__eq__(self) be called first if the type of other is a subclass of
>> the type of self.
>>
>
> Ah - yes. Half the logic is already on the __eq__ semantics - thanks.
> Well, I am updating that on my code right now.
>
> Anyway I am not seeing anyone opposing this going into col...abc.Sequence
> -
> Maybe it is ok for a BPO?
>
> (yes, there is this consideration I had, and also Guido,
> that it would create new behavior in classes that already exist, but I saw
> no way that could break code not specially crafted to break with this
> change.)
>
>
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