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

与@Kametrixom的答案在这里,我相信返回一个数组将比返回AnySequence更好,因为你可以访问所有数组的好东西,如计数等。

以下是改写后的内容:

public protocol EnumCollection : Hashable {}
extension EnumCollection {
    public static func allValues() -> [Self] {
        typealias S = Self
        let retVal = AnySequence { () -> AnyGenerator<S> in
            var raw = 0
            return AnyGenerator {
                let current : Self = withUnsafePointer(&raw) { UnsafePointer($0).memory }
                guard current.hashValue == raw else { return nil }
                raw += 1
                return current
            }
        }

        return [S](retVal)
    }
}

其他回答

这篇文章是相关的https://www.swift-studies.com/blog/2014/6/10/enumerating-enums-in-swift

基本上,提议的解决方案是

enum ProductCategory : String {
     case Washers = "washers", Dryers = "dryers", Toasters = "toasters"

     static let allValues = [Washers, Dryers, Toasters]
}

for category in ProductCategory.allValues{
     //Do something
}

我发现自己在代码中经常使用. allvalues。我终于找到了一种方法来简单地遵循Iteratable协议并拥有一个rawValues()方法。

protocol Iteratable {}
extension RawRepresentable where Self: RawRepresentable {

    static func iterateEnum<T: Hashable>(_: T.Type) -> AnyIterator<T> {
        var i = 0
        return AnyIterator {
            let next = withUnsafePointer(to: &i) {
                $0.withMemoryRebound(to: T.self, capacity: 1) { $0.pointee }
            }
            if next.hashValue != i { return nil }
            i += 1
            return next
        }
    }
}

extension Iteratable where Self: RawRepresentable, Self: Hashable {
    static func hashValues() -> AnyIterator<Self> {
        return iterateEnum(self)
    }

    static func rawValues() -> [Self.RawValue] {
        return hashValues().map({$0.rawValue})
    }
}


// Example
enum Grocery: String, Iteratable {
    case Kroger = "kroger"
    case HEB = "h.e.b."
    case Randalls = "randalls"
}

let groceryHashes = Grocery.hashValues() // AnyIterator<Grocery>
let groceryRawValues = Grocery.rawValues() // ["kroger", "h.e.b.", "randalls"]

这个问题现在简单多了。以下是我的Swift 4.2解决方案:

enum Suit: Int, CaseIterable {
  case None
  case Spade, Heart, Diamond, Club

  static let allNonNullCases = Suit.allCases[Spade.rawValue...]
}

enum Rank: Int, CaseIterable {
  case Joker
  case Two, Three, Four, Five, Six, Seven, Eight
  case Nine, Ten, Jack, Queen, King, Ace

  static let allNonNullCases = Rank.allCases[Two.rawValue...]
}

func makeDeck(withJoker: Bool = false) -> [Card] {
  var deck = [Card]()
  for suit in Suit.allNonNullCases {
    for rank in Rank.allNonNullCases {
      deck.append(Card(suit: suit, rank: rank))
    }
  }
  if withJoker {
    deck.append(Card(suit: .None, rank: .Joker))
  }
  return deck
}

4。2:

我喜欢这个解决方案,我把找到“列表理解在Swift”。

它使用Int rawws而不是string,但它避免了键入两次,它允许自定义范围,并且不硬编码原始值。

这是我最初解决方案的Swift 4版本,但请参阅上面的4.2改进:

enum Suit: Int {
  case None
  case Spade, Heart, Diamond, Club

  static let allRawValues = Suit.Spade.rawValue...Suit.Club.rawValue
  static let allCases = Array(allRawValues.map{ Suit(rawValue: $0)! })
}
enum Rank: Int {
  case Joker
  case Two, Three, Four, Five, Six
  case Seven, Eight, Nine, Ten
  case Jack, Queen, King, Ace

  static let allRawValues = Rank.Two.rawValue...Rank.Ace.rawValue
  static let allCases = Array(allRawValues.map{ Rank(rawValue: $0)! })
}
func makeDeck(withJoker: Bool = false) -> [Card] {
  var deck = [Card]()
  for suit in Suit.allCases {
    for rank in Rank.allCases {
      deck.append(Card(suit: suit, rank: rank))
    }
  }
  if withJoker {
    deck.append(Card(suit: .None, rank: .Joker))
  }
  return deck
}

我使用计算属性,它返回所有值的数组(感谢这篇文章http://natecook.com/blog/2014/10/loopy-random-enum-ideas/)。但是,它也使用int原始值,但我不需要在单独的属性中重复枚举的所有成员。

Xcode 6.1在如何使用rawValue获取enum成员方面做了一点改变,所以我修正了listing。还修复了第一个rawValue错误的小错误。

enum ValidSuits: Int {
    case Clubs = 0, Spades, Hearts, Diamonds
    func description() -> String {
        switch self {
        case .Clubs:
            return "♣︎"
        case .Spades:
            return "♠︎"
        case .Diamonds:
            return "♦︎"
        case .Hearts:
            return "♥︎"
        }
    }

    static var allSuits: [ValidSuits] {
        return Array(
            SequenceOf {
                () -> GeneratorOf<ValidSuits> in
                var i=0
                return GeneratorOf<ValidSuits> {
                    return ValidSuits(rawValue: i++)
                }
            }
        )
    }
}

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