Class and instance related questions.

[Asaf Las]

Hi Chris 

Thanks for answers 

On Friday, January 24, 2014 6:37:29 PM UTC+2, Chris Angelico wrote:
> On Sat, Jan 25, 2014 at 3:31 AM, Asaf Las <r... at gmail.com> wrote:
> > Hi
> > Is there way to get list of instances of particular
> > class through class itself? via metaclass or any other method?
> Not automatically, but you can make a class that keeps track of its
> instances with a weak reference system.

By "not automatically" do you mean there is no way to get references to instances of class via python's provided methods or attributes for class
object at time the class object is created? 

And usage of weak reference was suggested only to allow class instances 
garbage collected if for example class static container attribute will be 
used as class instance reference storage?

> > Another question - if class is object is it possible
> > to delete it? If it is possible then how instances
> > of that class will behave?
> 
> It's possible to unbind the name, but every instance retains a
> reference to its class, so the class itself won't disappear until
> there are no instances left of it.
> 
> ChrisA

That is interesting. Is it also reference count mechanism or something else?

Thanks 

Asaf