A Descriptor class implementing weakref properties in Python
Project description
Add a property that acts like a normal attribute, but keeps a weak reference to anything that is assigned to it.
Example:
First let’s define WeakValue using WeakProperty and SomeClass that will be weakly referenced:
>>> import weakref_property >>> import gc >>> class WeakValue(object): ... value = weakref_property.WeakProperty('value') >>> class SomeClass(object): ... passYou can assign and retrieve a value:
>>> a = SomeClass() >>> obj = WeakValue() >>> obj.value = a >>> obj.value # doctest: +ELLIPSIS <__main__.SomeClass object at ...>But it is kept as a weakref, so it can get collected. If it is collected, the property returns None:
>>> del a >>> gc.collect() # force gc to collect `a` object 0 >>> obj.valueYou can also delete the value completelly:
>>> del obj.value >>> obj.value Traceback (most recent call last): ... AttributeError: 'WeakValue' object has no attribute 'value'Sadly, weakrefs do not work on tuples, ints and not-subclassed lists and dicts:
>>> obj.value = [] Traceback (most recent call last): ... TypeError: cannot create weak reference to 'list' object
Project details
Release history Release notifications
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
Filename, size | File type | Python version | Upload date | Hashes |
---|---|---|---|---|
Filename, size weakref_property-0.1.tar.gz (14.4 kB) | File type Source | Python version None | Upload date | Hashes View hashes |