Re: [pygame] Why does Rect and Surface have copy method when copy exist in std-lib?

[Martin Kühne]

What we've established so far:

- copy.copy is considered an import "hurdle"
- which is why many modules implement a .copy() function to
- both of which basically wrap an internal .__copy__() function whose
direct use appears to be discouraged

At the end of the day I think you should decide what your code needs
to do: if copying an object or resource is a natural thing to do you
want to provide for your users, implement a __copy__ function. Adding
a line copy = __copy__ underneath would hence be a good thing to do to
encourage and ease use. In some cases, a copy of an object may be
nontrivial to create or, for example with system resource you rather
want to not provide anything like it, don't provide __copy__ and skip
this part.

cheers!
mar77i

Re: [pygame] Why does Rect and Surface have copy method when copy exist in std-lib?

[Victor Blomqvist]

Yes, I have seen that. There is a bunch of other libraries that does it as
well, such as numpy.copy pandas.DataFrame.copy.

The reason why I ask is that I have a library (pymunk) where I just
implemented pickle support, and I now have the option to either be
satisfied with copy.deepcopy which comes for free from pickle, or add a
custom copy method just like pygame has done.

To me it seems like having a custom copy goes against the python zen "There
should be one-- and preferably only one --obvious way to do it.". At the
same time many libraries have custom copy method, just as you noted.


On Sat, Jun 3, 2017 at 11:26 PM, Daniel Foerster 
wrote:

> Allow me to point out that there's such a thing as dict.copy(). It's
> pointless to import a module to call a method that you know is made
> publicly available already, and just as pointless to make people import.
>
> On Jun 3, 2017 16:23, "Victor Blomqvist"  wrote:
>
>> It seems like such a small performance difference shouldnt affect the
>> decision if a custom copy method is good or not?
>>
>> /Victor
>>
>> On Thu, Jun 1, 2017 at 9:24 PM, Jason Marshall <
>> jasonmarshall...@gmail.com> wrote:
>>
>>> In the C code, rect.copy and surface.copy are equivalent to
>>> rect.__copy__ and surface.__copy__. You may use copy.copy(rect) and
>>> copy.copy(surface) in your code, but copy.copy will simply call
>>> rect.__copy__ or surface.__copy__. By using rect.copy and surface.copy
>>> rather than the standard library's copy.copy, your code will run
>>> ≈0.0001% faster.
>>>
>>> For aesthetic reasons, you would use rect.copy and surface.copy rather
>>> than rect.__copy__ and surface.__copy__ in your code.
>>>
>>> Jason
>>>
>>> On Mon, May 29, 2017 at 3:38 PM, Victor Blomqvist  wrote:
>>> > Hello,
>>> >
>>> > Something I have been thinking about:
>>> > Rect and Surface classes have their own copy methods. Why do they have
>>> that
>>> > when there is a module called copy in the standard lib that can handle
>>> copy
>>> > (with help)? The rect copy method was added in pygame 1.9 so it is
>>> fairly
>>> > recent.
>>> >
>>> > http://pygame.org/docs/ref/rect.html#pygame.Rect.copy
>>> > https://docs.python.org/2/library/copy.html
>>> >
>>> > Thanks for any insights!
>>> > /Victor
>>>
>>
>>