我该怎么做indexOfObject或正确的containsObject [英] How do I do indexOfObject or a proper containsObject

问题描述

使用数组：我怎样做 indexOfObject 或正确的 containsObject

With an array: How do I do indexOfObject or a proper containsObject?

我的意思是，我知道我可以只弥合Array对的NSArray 并做到这一点有^^

但必须有这样做的'本土'的方式

I mean I know I could just bridge the Array to NSArray and do it there ^^
But there must be a 'native' way of doing this

P.S。为 containsObject 我想我可以在阵列筛选过但的indexOf 的？

P.S. for the containsObject I guess I could filter the array too but for indexOf?

推荐答案

您可以使用内置的找到，从而避免桥接Objective-C的 - 但只如果你的元素类型是<一个href=\"https://developer.apple.com/library/ios/documentation/General/Reference/SwiftStandardLibraryReference/Equatable.html\">Equatable. （如果不是Equatable，可以用一个比较函数和延伸使它左右。）

You can use the built-in find, and thus avoid bridging to Objective-C — but only if your element type is Equatable. (If it isn't Equatable, you can make it so with a comparison function and an extension.)

例如：

func == (lhs:Piece,rhs:Piece) -> Bool {
    return lhs.val == rhs.val
}

class Piece:Equatable,Printable {
    var val : Int
    var description : String { return String(val) }
    init (_ v:Int) {
        val = v
    }
}

现在你可以叫找到（ARR，P），其中改编是阵列＆LT样片方式＆gt; 和 p 是片

Now you can call find(arr,p) where arr is an Array<Piece> and p is a Piece.

一旦你有了这个，你可以开发基于它的实用程序。例如，这里是一个全球性的功能，以从数组中删除一个对象而桥接Objective-C的：

Once you have this, you can develop utilities based on it. For example, here's a global function to remove an object from an array without bridging to Objective-C:

func removeObject<T:Equatable>(inout arr:Array<T>, object:T) -> T? {
    if let found = find(arr,object) {
        return arr.removeAtIndex(found)
    }
    return nil
}

和测试它是这样的：

var arr = [Piece(1), Piece(2), Piece(3)]
removeObject(&arr,Piece(2))
println(arr)

---

您可以为NSObject的子类做到这一点。例如：

---

You can do this for NSObject subclasses too. Example:

func == (v1:UIView, v2:UIView) -> Bool {
    return v1.isEqual(v2)
}
extension UIView : Equatable {}

现在你可以叫找到上的UIView数组。这有点在一个痛苦的对接，不过，不必为每一个班级做到这一点，你希望能够使用找到在该类的一个数组。我已经提交了增强请求与苹果公司要求所有NSObject的子类被认为Equatable和 == 应该求助于的isEqual：的自动的

Now you can call find on an Array of UIView. It's sort of a pain in the butt, though, having to do this for every single class where you want to be able to use find on an Array of that class. I have filed an enhancement request with Apple requesting that all NSObject subclasses be considered Equatable and that == should fall back on isEqual: automatically.

修改种子3开始，这个的是的自动对的UIView和其他NSObject的类。因此，找到现在只是为他们工作。

EDIT Starting in Seed 3, this is automatic for UIView and other NSObject classes. So find now just works for them.

编辑2 在雨燕2.0​​开始，的indexOf 将存在一个方法：

EDIT 2 Starting in Swift 2.0, indexOf will exist as a method:

let s = ["Manny", "Moe", "Jack"]
let ix = s.indexOf("Moe") // 1

替代地，它需要一个返回布尔函数：

Alternatively, it takes a function that returns Bool:

let ix2 = s.indexOf {$0.hasPrefix("J")} // 2

同样，这仅适用于Equatable的集合，因为很明显，你无法找到一个大海捞针，除非你有识别针的方式，当你来到它。

Again, this works only on collections of Equatable, since obviously you cannot locate a needle in a haystack unless you have a way of identifying a needle when you come to it.

编辑3 雨燕2.0​​还引入了协议扩展。这意味着我可以重写我的整体功能的removeObject 作为一种方法！

EDIT 3 Swift 2.0 also introduces protocol extensions. This means I can rewrite my global function removeObject as a method!

例如：

extension RangeReplaceableCollectionType where Generator.Element : Equatable {
    mutating func removeObject(object:Self.Generator.Element) {
        if let found = self.indexOf(object) {
            self.removeAtIndex(found)
        }
    }
}

由于采用阵列RangeReplaceableCollectionType，现在我可以写code是这样的：

Since Array adopts RangeReplaceableCollectionType, now I can write code like this:

var arr = [Piece(1), Piece(2), Piece(3)]
arr.removeObject(Piece(2))

呵呵，快乐每一天！

Oh, happy day!

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