---
title: CFDictionary
framework: corefoundation
role: symbol
role_heading: Class
path: corefoundation/cfdictionary
---

# CFDictionary

## Declaration

```swift
class CFDictionary
```

## Overview

Overview CFDictionary and its derived mutable type, CFMutableDictionary, manage associations of key-value pairs. CFDictionary creates static dictionaries where you set the key-value pairs when first creating a dictionary and cannot modify them afterward; CFMutableDictionary creates dynamic dictionaries where you can add or delete key-value pairs at any time, and the dictionary automatically allocates memory as needed. A key-value pair within a dictionary is called an entry. Each entry consists of one object that represents the key and a second object that is that key’s value. Within a dictionary, the keys are unique. That is, no two keys in a single dictionary are equal (as determined by the equal callback). Internally, a dictionary uses a hash table to organize its storage and to provide rapid access to a value given the corresponding key. Keys for a CFDictionary may be of any C type, however note that if you want to convert a CFPropertyList to XML, any dictionary’s keys must be CFString objects. You create static dictionaries using either the CFDictionaryCreate(_:_:_:_:_:_:) or CFDictionaryCreateCopy(_:_:) function. Key-value pairs are passed as parameters to CFDictionaryCreate(_:_:_:_:_:_:). 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. CFDictionary provides functions for querying the values of a dictionary. The function CFDictionaryGetCount(_:) returns the number of key-value pairs in a dictionary; the CFDictionaryContainsValue(_:_:) function checks if a value is in a dictionary; and CFDictionaryGetKeysAndValues(_:_:_:) returns a C array containing all the values and a C array containing all the keys in a dictionary. The CFDictionaryApplyFunction(_:_:_:) function lets you apply a function to all key-value pairs in a dictionary. CFDictionary is “toll-free bridged” with its Cocoa Foundation counterpart, NSDictionary. This means that the Core Foundation type is interchangeable in function or method calls with the bridged Foundation object. Therefore, in a method where you see an NSDictionary * parameter, you can pass in a CFDictionaryRef, and in a function where you see a CFDictionaryRef parameter, you can pass in an NSDictionary instance. This also applies to concrete subclasses of NSDictionary. See Toll-Free Bridged Types for more information on toll-free bridging.

## Topics

### Creating a dictionary

- [CFDictionaryCreate(_:_:_:_:_:_:)](corefoundation/cfdictionarycreate(_:_:_:_:_:_:).md)
- [CFDictionaryCreateCopy(_:_:)](corefoundation/cfdictionarycreatecopy(_:_:).md)

### Examining a dictionary

- [CFDictionaryContainsKey(_:_:)](corefoundation/cfdictionarycontainskey(_:_:).md)
- [CFDictionaryContainsValue(_:_:)](corefoundation/cfdictionarycontainsvalue(_:_:).md)
- [CFDictionaryGetCount(_:)](corefoundation/cfdictionarygetcount(_:).md)
- [CFDictionaryGetCountOfKey(_:_:)](corefoundation/cfdictionarygetcountofkey(_:_:).md)
- [CFDictionaryGetCountOfValue(_:_:)](corefoundation/cfdictionarygetcountofvalue(_:_:).md)
- [CFDictionaryGetKeysAndValues(_:_:_:)](corefoundation/cfdictionarygetkeysandvalues(_:_:_:).md)
- [CFDictionaryGetValue(_:_:)](corefoundation/cfdictionarygetvalue(_:_:).md)
- [CFDictionaryGetValueIfPresent(_:_:_:)](corefoundation/cfdictionarygetvalueifpresent(_:_:_:).md)

### Applying a function to a dictionary

- [CFDictionaryApplyFunction(_:_:_:)](corefoundation/cfdictionaryapplyfunction(_:_:_:).md)

### Getting the CFDictionary type ID

- [CFDictionaryGetTypeID()](corefoundation/cfdictionarygettypeid().md)

### Callbacks

- [CFDictionaryApplierFunction](corefoundation/cfdictionaryapplierfunction.md)
- [CFDictionaryCopyDescriptionCallBack](corefoundation/cfdictionarycopydescriptioncallback.md)
- [CFDictionaryEqualCallBack](corefoundation/cfdictionaryequalcallback.md)
- [CFDictionaryHashCallBack](corefoundation/cfdictionaryhashcallback.md)
- [CFDictionaryReleaseCallBack](corefoundation/cfdictionaryreleasecallback.md)
- [CFDictionaryRetainCallBack](corefoundation/cfdictionaryretaincallback.md)

### Data Types

- [CFDictionaryKeyCallBacks](corefoundation/cfdictionarykeycallbacks.md)
- [CFDictionaryValueCallBacks](corefoundation/cfdictionaryvaluecallbacks.md)

### Constants

- [Predefined Callback Structures](corefoundation/cfdictionary-predefined-callback-structures.md)

## Relationships

### Inherited By

- [CFMutableDictionary](corefoundation/cfmutabledictionary.md)

### Conforms To

- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)

## See Also

### Related Documentation

- [Property List Programming Topics for Core Foundation](apple-archive/documentation/CoreFoundation/Conceptual/CFPropertyLists.md)
- [Collections Programming Topics for Core Foundation](apple-archive/documentation/CoreFoundation/Conceptual/CFCollections.md)

### Opaque Types

- [CFAllocator](corefoundation/cfallocator.md)
- [CFArray](corefoundation/cfarray.md)
- [CFAttributedString](corefoundation/cfattributedstring.md)
- [CFBag](corefoundation/cfbag.md)
- [CFBinaryHeap](corefoundation/cfbinaryheap.md)
- [CFBitVector](corefoundation/cfbitvector.md)
- [CFBoolean](corefoundation/cfboolean.md)
- [CFBundle](corefoundation/cfbundle.md)
- [CFCalendar](corefoundation/cfcalendar.md)
- [CFCharacterSet](corefoundation/cfcharacterset.md)
- [CFData](corefoundation/cfdata.md)
- [CFDate](corefoundation/cfdate.md)
- [CFDateFormatter](corefoundation/cfdateformatter.md)
- [CFError](corefoundation/cferror.md)
- [CFFileDescriptor](corefoundation/cffiledescriptor.md)