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Python | Use of __slots__ slots provide a special mechanism to reduce the size of objects.It is a concept of memory optimisation on objects.
__weakref__ is just an opaque object that references all the weak references to the current object. In actual fact it's an instance of weakref (or sometimes weakproxy ) which is both a weak reference to the object and part of a doubly linked list to all weak references for that object.
Slots in Python is a special mechanism that is used to reduce memory of the objects. In Python, all the objects use a dynamic dictionary for adding an attribute. Slots is a static type method in this no dynamic dictionary are required for allocating attribute.
weakref.proxy(object[,callback])Returns a proxy to the object that uses a weak reference. The returned object has type ProxyType or CallableProxyType, depending on if the object is callable. These objects are not hashable.
Consider the following code:
from weakref import ref
class Klass(object):
# __slots__ = ['foo']
def __init__(self):
self.foo = 'bar'
k = Klass()
r = ref(k)
it works but when I uncomment the __slots__ it breaks with TypeError: "cannot create weak reference to 'Klass' object" under Python 2.6.
Please, does anyone know if this is an inherent limitation of Python and __slots__ or if it is a bug? How to work-around it?
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