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📖 Name

weakref.WeakValueDictionary — A mapping class that references values weakly. Entries are discarded when no strong reference to the value exists.

🚀 Quick Reference

Use Case	Command	Description
Create a weak-value dictionary	WeakValueDictionary()	Empty dictionary, or initialize with other mapping/iterable
Get value by key	d[key]	Returns the value, raises KeyError if missing
Set value	d[key] = value	Stores a weak reference to value
Delete entry	del d[key]	Removes the key-value pair
Check membership	key in d	Returns True if key exists
Get with default	d.get(key, default=None)	Return value or default if missing
Iterate keys	iter(d) or d.keys()	Returns an iterator over keys
Iterate values	d.values()	Returns a view of values (weak references may be dead)
Iterate items	d.items()	Returns a view of key-value pairs
Pop item	d.pop(key, *args)	Remove and return value; raises KeyError if missing and no default
Pop arbitrary item	d.popitem()	Remove and return (key, value) pair; raises KeyError if empty
Set default	d.setdefault(key, default=None)	Return value if key exists, else set and return default
Update from another mapping	d.update(other, **kwargs)	Merge keys/values from other and keyword arguments
Copy	d.copy()	Returns a shallow copy (values are still weak references)
Clear all entries	d.clear()	Remove all items (inherited from MutableMapping)
Get weak refs to values	d.valuerefs()	Returns a list of weak reference objects to values
Iterate weak refs to values	d.itervaluerefs()	Returns an iterator of weak reference objects

📝 Description

Mapping class that references values weakly. Entries in the dictionary will be discarded when no strong reference to the value exists anymore.

🏗️ Method Resolution Order

• WeakValueDictionary
• collections.abc.MutableMapping
• collections.abc.Mapping
• collections.abc.Collection
• collections.abc.Sized
• collections.abc.Iterable
• collections.abc.Container
• builtins.object

⚙️ Methods Defined Here

• __contains__(self, key)
• __copy__ = copy(self)
• __deepcopy__(self, memo)
• __delitem__(self, key)
• __getitem__(self, key)
• __init__(self, other=(), /, **kw) — Initialize self. See help(type(self)) for accurate signature.
• __ior__(self, other)
• __iter__ = keys(self)
• __len__(self)
• __or__(self, other) — Return self|value.
• __repr__(self) — Return repr(self).
• __ror__(self, other) — Return value|self.
• __setitem__(self, key, value)
• copy(self)
• get(self, key, default=None) — D.get(k[,d]) → D[k] if k in D, else d. d defaults to None.
• items(self) — D.items() → a set-like object providing a view on D's items
• itervaluerefs(self) — Return an iterator that yields the weak references to the values. The references are not guaranteed to be 'live' at the time they are used, so the result of calling the references needs to be checked before being used. This can be used to avoid creating references that will cause the garbage collector to keep the values around longer than needed.
• keys(self) — D.keys() → a set-like object providing a view on D's keys
• pop(self, key, *args) — D.pop(k[,d]) → v, remove specified key and return the corresponding value. If key is not found, d is returned if given, otherwise KeyError is raised.
• popitem(self) — D.popitem() → (k, v), remove and return some (key, value) pair as a 2-tuple; but raise KeyError if D is empty.
• setdefault(self, key, default=None) — D.setdefault(k[,d]) → D.get(k,d), also set D[k]=d if k not in D
• update(self, other=None, /, **kwargs) — D.update([E, ]**F) → None. Update D from mapping/iterable E and F. If E present and has a .keys() method, does: for k in E: D[k] = E[k]. If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v. In either case, this is followed by: for k, v in F.items(): D[k] = v.
• valuerefs(self) — Return a list of weak references to the values. The references are not guaranteed to be 'live' at the time they are used, so the result of calling the references needs to be checked before being used. This can be used to avoid creating references that will cause the garbage collector to keep the values around longer than needed.
• values(self) — D.values() → an object providing a view on D's values

📦 Data Descriptors Defined Here

• __dict__ — dictionary for instance variables (if defined)
• __weakref__ — list of weak references to the object (if defined)

📦 Data and Other Attributes Defined Here

• __abstractmethods__ = frozenset()

🔗 Methods Inherited from collections.abc.MutableMapping

• clear(self) — D.clear() → None. Remove all items from D.

🔗 Methods Inherited from collections.abc.Mapping

• __eq__(self, other) — Return self==value.

🔗 Data and Other Attributes Inherited from collections.abc.Mapping

• __hash__ = None
• __reversed__ = None

🔗 Class Methods Inherited from collections.abc.Collection

• __subclasshook__(C) from abc.ABCMeta — Abstract classes can override this to customize issubclass(). This is invoked early on by abc.ABCMeta.__subclasscheck__(). It should return True, False or NotImplemented. If it returns NotImplemented, the normal algorithm is used. Otherwise, it overrides the normal algorithm (and the outcome is cached).

🔗 Class Methods Inherited from collections.abc.Iterable

• __class_getitem__ = GenericAlias(...) from abc.ABCMeta — Represent a PEP 585 generic type. E.g. for t = list[int], t.__origin__ is list and t.__args__ is (int,).

📖 Name 🚀 Quick Reference 📝 Description 🏗️ Method Resolution Order ⚙️ Methods Defined Here 📦 Data Descriptors Defined Here 📦 Data and Other Attributes Defined Here 🔗 Methods Inherited from collections.abc.MutableMapping 🔗 Methods Inherited from collections.abc.Mapping 🔗 Data and Other Attributes Inherited from collections.abc.Mapping 🔗 Class Methods Inherited from collections.abc.Collection 🔗 Class Methods Inherited from collections.abc.Iterable