weakref list in python

Question

I\'m in need of a list of weak references that deletes items when they die. Currently the only way I have of doing this is to keep flushing the list (removing dead references ma

Answer 1

You can use WeakSet from the very same weakref module (it's actually defined elsewhere by the way, but it's imported there).

>>> from weakref import WeakSet
>>> s = WeakSet()
>>> class Obj(object): pass # can't weakref simple objects
>>> a = Obj()
>>> s.add(a)
>>> print len(s)
1
>>> del a
>>> print len(s)
0