Comparison of programming languages (associative array): Difference between revisions

Revision as of 04:33, 29 July 2020

Revision as of 01:20, 30 July 2020

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===Objective-C (Cocoa/GNUstep) ===

[[Cocoa (API)|Cocoa]] and [[GNUstep]], written in [[Objective-C]], handle associative arrays using <code>NSMutableDictionary</code> (a mutable version of <code>NSDictionary</code>) class cluster. This class allows assignments between any two objects. A copy of the key object is made before it is inserted into <code>NSMutableDictionary</code>, therefore the keys must conform to the <code>NSCopying</code> protocol. When being inserted to a dictionary, the value object receives a retain message to increase its reference count. The value object will receive the release message when it will be deleted from the dictionary (botheither explicitly or by adding to the dictionary a different object with the same key).

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To access assigned objects, this command may be used:

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All keys or values can be simply enumerated using <code>NSEnumerator</code>:

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OnIn Mac OS X 10.5+ and iPhone OS, dictionary keys can also be enumerated more concisely using thisthe [<code>NSFastEnumeration</code> construct:<ref>https://developer.apple.com/documentation/Cocoa/Reference/NSFastEnumeration_protocol/</ref> NSFastEnumeration] construct:

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And relevantRelevant fields can be quickly accessed using key paths:

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