Deleting objects

[Shalabh Chaturvedi]

user at domain.invalid wrote:
> Say I have an object (foo), that contains an
> array (bar) of references to other objects.
> 
> Now I want to puff some of the objects from the
> array so that I remove the array element, and
> destroy the oject.

You don't need to jump through hoops for this. All you need to do is:

del foo

If there are no other references to the object that was called foo 
above, then (and only then) it will be destroyed.

Python keeps a reference count for each object. When the count hits 0 
(no references pointing to object) it is destroyed.

Because of this, attributes of foo (eg foo.bar) will automatically be 
destroyed when foo is destroyed (assuming they don't have references 
from elsewhere).

> 
> but when I do:
> 
> del foo.bar[0]
> 
> Python says:
>  object doesn't support item deletion
> 
> So do I need to define __del__?  And what would I
> put there?

What is the type of foo.bar?

 >
> What if I wanted to remove the array element
> but still have the object exist?

del foo.bar

This will remove the reference foo.bar.

> What happens if I succeed in destroying an object
> that other objects still think they are referencing?

Try as you might, shooting yourself in the foot is pretty hard in Python 
(see above :)

--
Shalabh