What is the equivalent of Java's List in Objective-C?

Question

I wonder if Objective-C offers support for Lists? Or .. is NSMutableArray a way to go, instead?

Answer 1

Yes NSMutableArray (Mac, iOS) would in most cases be the appropriate class for lists (with NSArray being the immutable counterpart).

Contrary to Java's collection classes Objective-C's (or rather Foundation's) arrays are opaque class clusters that completely hide their implementation.

Edit: snip ^{(see comment by orange80)}

While Java has a ton of collection classes such as:

• HashSet
• TreeSet
• LinkedHashSet
• ArrayList
• LinkedList
• PriorityQueue
• HashMap
• TreeMap
• LinkedHashMap
• WeakHashMap
• IdentityHashMap
• CopyOnWriteArrayList
• CopyOnWriteArraySet
• EnumSet
• EnumMap
• ConcurrentLinkedQueue
• LinkedBlockingQueue
• ArrayBlockingQueue
• PriorityBlockingQueue
• DelayQueue
• SynchronousQueue
• ConcurrentHashMap

Objective-C however (again, actually the Foundation SDK) only provides a very limited number of collection classes:

• CFMutableDictionary
• CFMutableBag
• CFMutableBitVector
• CFMutableSet
• CFMutableArray
• CFBinaryHeap
• CFMutableTree

or preferably their NS-equivalents:

• NSMutableDictionary
• NSDictionary
• NSMutableSet
• NSSet
• NSCountedSet
• NSMutableArray
• NSArray

For a full insight in the matter I recommend this read: http://ridiculousfish.com/blog/posts/array.html (the author is a member of Apple's Foundation Team)

Answer 2

Generally speaking, you'll want to use NSMutableArray for equivalent behaviour (though the implementation is very different.) You also have the option of using CFMutableArray (a C-based API that is a little more flexible than NSMutableArray and is toll-free bridged with it.) If you're using C++ rather than (or in addition to) Objective-C, you have any of the STL collection types (such as std::list<T>, std::vector<T>, etc.) whose suitability will depend on your exact use case.