在 Swift 中:Array VS NSArray VS [AnyObject] 之间的区别 [英] in Swift: Difference between Array VS NSArray VS [AnyObject]

问题描述

正如标题所说，Array vs NSArray vs [AnyObject] 有什么区别?

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

此外，最推荐的处理方法是什么.我的意思是推荐的是，什么是最简单的实现.谢谢.

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

推荐答案

Array 是一个 struct，因此它是一个值类型迅速.NSArray 是一个不可变的 Objective C 类，因此它是 Swift 中的引用类型，并且它被桥接到 Array.NSMutableArray 是 NSArray 的可变子类.

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)

打印:

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

因为foo 改变了a 的本地值，而bar 改变了引用.如果你像其他引用类型一样使用 let arr 而不是 var ，它也可以工作.

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.

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