Remove and destroy object in a list

Question

Extending a little on this question. Removing an object from a Python list is easy enough, but I'm going to have a "busy" list -- frequent removals and frequent additions -- so I want to guard against memory leaks.

Will just removing the object from the list destroy the object? (I'm assuming No.)
If my assumption is correct, then how can I remove it from the list and destroy it at the same time?

If it matters, the objects in question are instances of a class that I wrote. I plan on creating the objects "live" each time I need to insert a new one, e.g.

myList.insert(index,myClass(constructorParm1,constructorParm2))

So when I later need to delete some of the instances created that way, I want to be sure they're not just gone from the list, but gone period.

If there are no more references to an object (in cPython, at least), it will be destroyed. — Wooble, Feb 15 '13 at 15:18

score 3 · Accepted Answer · answered Feb 15 '13 at 15:20

3

In cPython, objects are automatically destroyed when their reference count drops to 0.

If you delete a entry from your list, the reference count for the object in question is decremented. You do not need to do anything special to have it destroyed, nor should you try to. If any other reference to the object still exists, then destroying the object would break the other reference.

If you want to hold references to an object that do not stop the object from being garbage collected, use a weakref reference instead.

answered Feb 15 '13 at 15:20

Martijn Pieters

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I'm using Python 2.7. Does it do the same? If so, then great, no problem. – JDM Feb 15 '13 at 15:22
1

Python 2.7 is a cPython version, so yes it does. We are specifying this a cPython as opposed to Jython, IronPython or PyPy, which handle object lifetimes differently. – Martijn Pieters Feb 15 '13 at 15:23
"auto-reaped"? Is that a weird way of spelling - "garbage collected"? ;) – Jon Clements Feb 15 '13 at 15:23
@JonClements: I suppose it is; replaced. – Martijn Pieters Feb 15 '13 at 15:24

Remove and destroy object in a list

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