enum Suit: String {
    case spades = "♠"
    case hearts = "♥"
    case diamonds = "♦"
    case clubs = "♣"
}

例如,我怎么做这样的事情:

for suit in Suit {
    // do something with suit
    print(suit.rawValue)
}

结果示例:

♠
♥
♦
♣

当前回答

我发现了一种有点俗气但更安全的方法,它不需要键入两次值或引用枚举值的内存,因此不太可能损坏。

基本上,与其使用枚举,不如创建一个具有单个实例的结构体,并将所有enum-values设置为常量。然后可以使用Mirror查询变量

public struct Suit{

    // the values
    let spades = "♠"
    let hearts = "♥"
    let diamonds = "♦"
    let clubs = "♣"

    // make a single instance of the Suit struct, Suit.instance
    struct SStruct{static var instance: Suit = Suit()}
    static var instance : Suit{
        get{return SStruct.instance}
        set{SStruct.instance = newValue}
    }

    // an array with all of the raw values
    static var allValues: [String]{
        var values = [String]()

        let mirror = Mirror(reflecting: Suit.instance)
        for (_, v) in mirror.children{
            guard let suit = v as? String else{continue}
            values.append(suit)
        }

        return values
    }
}

如果使用此方法,则需要使用Suit.instance.clubs或Suit.instance.spades来获取单个值

但所有这些都太无聊了……让我们做一些事情,使它更像一个真正的enum!

public struct SuitType{

    // store multiple things for each suit
    let spades = Suit("♠", order: 4)
    let hearts = Suit("♥", order: 3)
    let diamonds = Suit("♦", order: 2)
    let clubs = Suit("♣", order: 1)

    struct SStruct{static var instance: SuitType = SuitType()}
    static var instance : SuitType{
        get{return SStruct.instance}
        set{SStruct.instance = newValue}
    }

    // a dictionary mapping the raw values to the values
    static var allValuesDictionary: [String : Suit]{
        var values = [String : Suit]()

        let mirror = Mirror(reflecting: SuitType.instance)
        for (_, v) in mirror.children{
            guard let suit = v as? Suit else{continue}
            values[suit.rawValue] = suit
        }

        return values
    }
}

public struct Suit: RawRepresentable, Hashable{
    public var rawValue: String
    public typealias RawValue = String

    public var hashValue: Int{
        // find some integer that can be used to uniquely identify
        // each value. In this case, we could have used the order
        // variable because it is a unique value, yet to make this
        // apply to more cases, the hash table address of rawValue
        // will be returned, which should work in almost all cases
        // 
        // you could also add a hashValue parameter to init() and
        // give each suit a different hash value
        return rawValue.hash
    }

    public var order: Int
    public init(_ value: String, order: Int){
        self.rawValue = value
        self.order = order
    }

    // an array of all of the Suit values
    static var allValues: [Suit]{
        var values = [Suit]()

        let mirror = Mirror(reflecting: SuitType.instance)
        for (_, v) in mirror.children{
            guard let suit = v as? Suit else{continue}
            values.append(suit)
        }

        return values
    }

    // allows for using Suit(rawValue: "♦"), like a normal enum
    public init?(rawValue: String){
        // get the Suit from allValuesDictionary in SuitType, or return nil if that raw value doesn't exist
        guard let suit = SuitType.allValuesDictionary[rawValue] else{return nil}
        // initialize a new Suit with the same properties as that with the same raw value
        self.init(suit.rawValue, order: suit.order)
    }
}

你现在可以做

let allSuits: [Suit] = Suit.allValues

or

for suit in Suit.allValues{
   print("The suit \(suit.rawValue) has the order \(suit.order)")
}

然而,要获得一个单一,你仍然需要使用SuitType.instance.spades或SuitType.instance.hearts。为了更加直观,您可以向Suit添加一些允许您使用Suit.type的代码。*而不是SuitType.instance.*

public struct Suit: RawRepresentable, Hashable{
   // ...your code...

   static var type = SuitType.instance

   // ...more of your code...
}

您现在可以使用Suit.type.diamonds而不是SuitType.instance。diamonds,或者Suit.type.clubs而不是SuitType.instance.clubs

其他回答

Xcode 10与Swift 4.2

enum Filter: String, CaseIterable {

    case salary = "Salary"
    case experience = "Experience"
    case technology = "Technology"
    case unutilized = "Unutilized"
    case unutilizedHV = "Unutilized High Value"

    static let allValues = Filter.allCases.map { $0.rawValue }
}

叫它

print(Filter.allValues)

打印:

[“薪酬”、“经验”、“技术”、“未利用”、“未利用的高价值”]


旧版本

对于表示Int的enum

enum Filter: Int {
    case salary
    case experience
    case technology
    case unutilized
    case unutilizedHV
    
    static let allRawValues = salary.rawValue...unutilizedHV.rawValue  // First to last case
    static let allValues = allRawValues.map { Filter(rawValue: $0)!.rawValue }
}

这样叫它:

print(Filter.allValues)

打印:

[0, 1, 2, 3, 4]


用于表示字符串的enum

enum Filter: Int {
    case salary
    case experience
    case technology
    case unutilized
    case unutilizedHV
    
    static let allRawValues = salary.rawValue...unutilizedHV.rawValue  // First to last case
    static let allValues = allRawValues.map { Filter(rawValue: $0)!.description }
}

extension Filter: CustomStringConvertible {
    var description: String {
        switch self {
        case .salary: return "Salary"
        case .experience: return "Experience"
        case .technology: return "Technology"
        case .unutilized: return "Unutilized"
        case .unutilizedHV: return "Unutilized High Value"
        }
    }
}

叫它

print(Filter.allValues)

打印:

[“薪酬”、“经验”、“技术”、“未利用”、“未利用的高价值”]

实验内容是: 实验

在Card中添加一个方法,用于创建一副完整的牌,每一副牌都是rank和花色的组合。

因此,除了添加方法之外,没有修改或增强给定的代码(并且没有使用还没有教过的东西),我想出了这个解决方案:

struct Card {
    var rank: Rank
    var suit: Suit

    func simpleDescription() -> String {
        return "The \(rank.simpleDescription()) of \(suit.simpleDescription())"
    }

    func createDeck() -> [Card] {
        var deck: [Card] = []
        for rank in Rank.Ace.rawValue...Rank.King.rawValue {
            for suit in Suit.Spades.rawValue...Suit.Clubs.rawValue {
                let card = Card(rank: Rank(rawValue: rank)!, suit: Suit(rawValue: suit)!)
                //println(card.simpleDescription())
                deck += [card]
            }
        }
        return deck
    }
}
let threeOfSpades = Card(rank: .Three, suit: .Spades)
let threeOfSpadesDescription = threeOfSpades.simpleDescription()
let deck = threeOfSpades.createDeck()

更新到Swift 2.2+

func iterateEnum<T: Hashable>(_: T.Type) -> AnyGenerator<T> {
    var i = 0
    return AnyGenerator {
        let next = withUnsafePointer(&i) {
            UnsafePointer<T>($0).memory
        }
        if next.hashValue == i {
            i += 1
            return next
        } else {
            return nil
        }
    }
}

它更新了Swift 2.2表单@Kametrixom的答案

Swift 3.0+(非常感谢@Philip)

func iterateEnum<T: Hashable>(_: T.Type) -> AnyIterator<T> {
    var i = 0
    return AnyIterator {
        let next = withUnsafePointer(&i) {
            UnsafePointer<T>($0).pointee
        }
        if next.hashValue == i {
            i += 1
            return next
        } else {
            return nil
        }
    }
}

如果您仍然想为Rank和Suit使用枚举,这里有一个不那么神秘的例子。如果您想使用for-in循环遍历每个对象,只需将它们收集到一个Array中。

标准52张牌的例子:

enum Rank: Int {
    case Ace = 1, Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten, Jack, Queen, King
    func name() -> String {
        switch self {
        case .Ace:
            return "ace"
        case .Jack:
            return "jack"
        case .Queen:
            return "queen"
        case .King:
            return "king"
        default:
            return String(self.toRaw())
        }
    }
}

enum Suit: Int {
    case Diamonds = 1, Clubs, Hearts, Spades
    func name() -> String {
        switch self {
        case .Diamonds:
            return "diamonds"
        case .Clubs:
            return "clubs"
        case .Hearts:
            return "hearts"
        case .Spades:
            return "spades"
        default:
            return "NOT A VALID SUIT"
        }
    }
}

let Ranks = [
    Rank.Ace,
    Rank.Two,
    Rank.Three,
    Rank.Four,
    Rank.Five,
    Rank.Six,
    Rank.Seven,
    Rank.Eight,
    Rank.Nine,
    Rank.Ten,
    Rank.Jack,
    Rank.Queen,
    Rank.King
]

let Suits = [
    Suit.Diamonds,
    Suit.Clubs,
    Suit.Hearts,
    Suit.Spades
]


class Card {
    var rank: Rank
    var suit: Suit

    init(rank: Rank, suit: Suit) {
        self.rank = rank
        self.suit = suit
    }
}

class Deck {
    var cards = Card[]()

    init() {
        for rank in Ranks {
            for suit in Suits {
                cards.append(Card(rank: rank, suit: suit))
            }
        }
    }
}

var myDeck = Deck()
myDeck.cards.count  // => 52

在处理Swift 2.0时,以下是我的建议:

我已经将原始类型添加到Suit enum

enum Suit: Int {

然后:

struct Card {
    var rank: Rank
    var suit: Suit


    func fullDeck()-> [Card] {

        var deck = [Card]()

        for i in Rank.Ace.rawValue...Rank.King.rawValue {

            for j in Suit.Spades.rawValue...Suit.Clubs.rawValue {

                deck.append(Card(rank:Rank(rawValue: i)! , suit: Suit(rawValue: j)!))
            }
        }

        return deck
    }
}