# CFMutableDictionary ``` class CFMutableDictionary ``` ## Overview CFMutableDictionary manages dynamic dictionaries. The basic interface for managing dictionaries is provided by [`CFDictionary`](/documentation/CoreFoundation/CFDictionary). CFMutableDictionary adds functions to modify the contents of a dictionary. You create a mutable dictionary object using either the [`CFDictionaryCreateMutable(_:_:_:_:)`](/documentation/CoreFoundation/CFDictionaryCreateMutable(_:_:_:_:)) or [`CFDictionaryCreateMutableCopy(_:_:_:)`](/documentation/CoreFoundation/CFDictionaryCreateMutableCopy(_:_:_:)) function. You can add key-value pairs using the [`CFDictionaryAddValue(_:_:_:)`](/documentation/CoreFoundation/CFDictionaryAddValue(_:_:_:)) and [`CFDictionarySetValue(_:_:_:)`](/documentation/CoreFoundation/CFDictionarySetValue(_:_:_:)) functions. When adding key-value pairs to a dictionary, the keys and values are not copied—they are retained so they are not invalidated before the dictionary is deallocated. You can remove key-value pairs using the [`CFDictionaryRemoveValue(_:_:)`](/documentation/CoreFoundation/CFDictionaryRemoveValue(_:_:)) function. When removing key-value pairs from a dictionary, the keys and values are released. CFMutableDictionary is “toll-free bridged” with its Cocoa Foundation counterpart, . What this means is that the Core Foundation type is interchangeable in function or method calls with the bridged Foundation object. This means that in a method where you see an `NSMutableDictionary *` parameter, you can pass in a `CFMutableDictionaryRef`, and in a function where you see a `CFMutableDictionaryRef` parameter, you can pass in an NSMutableDictionary instance. This also applies to concrete subclasses of NSMutableDictionary. See [Toll-Free Bridged Types](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFDesignConcepts/Articles/tollFreeBridgedTypes.html#//apple_ref/doc/uid/TP40010677) for more information on toll-free bridging. ## Topics ### Creating a Mutable Dictionary [`CFDictionaryCreateMutable(_:_:_:_:)`](/documentation/CoreFoundation/CFDictionaryCreateMutable(_:_:_:_:)) Creates a new mutable dictionary. [`CFDictionaryCreateMutableCopy(_:_:_:)`](/documentation/CoreFoundation/CFDictionaryCreateMutableCopy(_:_:_:)) Creates a new mutable dictionary with the key-value pairs from another dictionary. ### Modifying a Dictionary [`CFDictionaryAddValue(_:_:_:)`](/documentation/CoreFoundation/CFDictionaryAddValue(_:_:_:)) Adds a key-value pair to a dictionary if the specified key is not already present. [`CFDictionaryRemoveAllValues(_:)`](/documentation/CoreFoundation/CFDictionaryRemoveAllValues(_:)) Removes all the key-value pairs from a dictionary, making it empty. [`CFDictionaryRemoveValue(_:_:)`](/documentation/CoreFoundation/CFDictionaryRemoveValue(_:_:)) Removes a key-value pair. [`CFDictionaryReplaceValue(_:_:_:)`](/documentation/CoreFoundation/CFDictionaryReplaceValue(_:_:_:)) Replaces a value corresponding to a given key. [`CFDictionarySetValue(_:_:_:)`](/documentation/CoreFoundation/CFDictionarySetValue(_:_:_:)) Sets the value corresponding to a given key. ## See Also [Property List Programming Topics for Core Foundation](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFPropertyLists/CFPropertyLists.html#//apple_ref/doc/uid/10000130i) [Collections Programming Topics for Core Foundation](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFCollections/CFCollections.html#//apple_ref/doc/uid/10000124i) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)