Re: [Python-Dev] Replacing self.__dict__ in __init__

Thank you to everyone who participated (Kirill, Raymond, Nick, Naoki). I've decided there are too many caveats for this approach to be worthwhile and I'm giving up on it. Kind regards, Tin On Sat, Mar 24, 2018 at 3:18 PM Tin Tvrtković wrote: > Hi Python-dev, > > I'm one

Re: [Python-Dev] Replacing self.__dict__ in __init__

On Mar 25, 2018, at 8:08 AM, Tin Tvrtković wrote: > > That's reassuring, thanks. I misspoke. The object size is the same but the underlying dictionary loses key-sharing and doubles in size. Raymond ___ Python-Dev mailing list

Re: [Python-Dev] Replacing self.__dict__ in __init__

> > The dict can be replaced during __init__() and still get benefits of > key-sharing. That benefit is lost only when the instance dict keys are > modified downstream from __init__(). So, from a dict size point of view, > your optimization is fine. > I think replacing __dict__ lose

Re: [Python-Dev] Replacing self.__dict__ in __init__

On Sun, Mar 25, 2018 at 9:51 AM, Serhiy Storchaka wrote: > 25.03.18 18:38, Tin Tvrtković пише: >> >> For example, for a simple class with 9 attributes: > What are results for classes with 2 or 100 attributes? What are results in > Python 3.5? > > I think you are playing on

Re: [Python-Dev] Replacing self.__dict__ in __init__

25.03.18 18:38, Tin Tvrtković пише: For example, for a simple class with 9 attributes: What are results for classes with 2 or 100 attributes? What are results in Python 3.5? I think you are playing on thin ice. Your results depend on implementation details of the bytecode (in particularly

Re: [Python-Dev] Replacing self.__dict__ in __init__

On Sun, Mar 25, 2018 at 5:23 AM Nick Coghlan wrote: > That depends on what you mean by "safe" :) > > It won't crash, but it will lose any existing entries that a metaclass, > subclass, or __new__ method implementation might have added to the instance > dictionary before

Re: [Python-Dev] Replacing self.__dict__ in __init__

That's reassuring, thanks. On Sat, Mar 24, 2018 at 5:20 PM Raymond Hettinger < raymond.hettin...@gmail.com> wrote: > This should work. I've seen it done in other production tools without any > ill effect. > > The dict can be replaced during __init__() and still get benefits of > key-sharing.

Re: [Python-Dev] Replacing self.__dict__ in __init__

On 25 March 2018 at 00:18, Tin Tvrtković wrote: > But is it safe to do on CPython? > That depends on what you mean by "safe" :) It won't crash, but it will lose any existing entries that a metaclass, subclass, or __new__ method implementation might have added to the

Re: [Python-Dev] Replacing self.__dict__ in __init__

> On Mar 24, 2018, at 7:18 AM, Tin Tvrtković wrote: > > it's faster to do this: > > self.__dict__ = {'a': a, 'b': b, 'c': c} > > i.e. to replace the instance dictionary altogether. On PyPy, their core devs > inform me this is a bad idea because the instance

Re: [Python-Dev] Replacing self.__dict__ in __init__

On Sat, Mar 24, 2018 at 02:18:14PM +, Tin Tvrtković wrote: > self.__dict__ = {'a': a, 'b': b, 'c': c} > > i.e. to replace the instance dictionary altogether. On PyPy, their core > devs inform me this is a bad idea because the instance dictionary is > special there, so we won't be doing

Re: [Python-Dev] Replacing self.__dict__ in __init__

2018-03-24 17:18 GMT+03:00 Tin Tvrtković : > > I've found that, if a class has more than one attribute, instead of > creating an init like this: > > self.a = a > self.b = b > self.c = c > > it's faster to do this: > > self.__dict__ = {'a': a, 'b': b, 'c': c} >

[Python-Dev] Replacing self.__dict__ in __init__

Hi Python-dev, I'm one of the core attrs contributors, and I'm contemplating applying an optimization to our generated __init__s. Before someone warns me python-dev is for the development of the language itself, there are two reasons I'm posting this here: 1) it's a very low level question that