in Swift: Difference between Array VS NSArray VS [AnyObject]

Question

As the title says, what's the difference between Array vs NSArray vs [AnyObject]?

Also, what is most recommended way of approaching this. What i mean recommended is, what's the easiest implementation. Thank you.

Answer 1

Array is a struct, therefore it is a value type in Swift. NSArray is an immutable Objective C class, therefore it is a reference type in Swift and it is bridged to Array<AnyObject>. NSMutableArray is the mutable subclass of NSArray.

var arr : NSMutableArray = ["Pencil", "Eraser", "Notebook"] var barr = ["Pencil", "Eraser", "Notebook"]  func foo (var a : Array<String>) {     a[2] = "Pen" }  func bar (a : NSMutableArray) {     a[2] = "Pen" }  foo(barr) bar(arr)  println (arr) println (barr) 

Prints:

(     Pencil,     Eraser,     Pen ) [Pencil, Eraser, Notebook] 

Because foo changes the local value of a and bar changes the reference. It will also work if you do let arr instead of var as with other reference types.