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:
♠
♥
♦
♣
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++)
}
}
)
}
}
其他回答
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"]
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”]
另一个解决方案:
enum Suit: String {
case spades = "♠"
case hearts = "♥"
case diamonds = "♦"
case clubs = "♣"
static var count: Int {
return 4
}
init(index: Int) {
switch index {
case 0: self = .spades
case 1: self = .hearts
case 2: self = .diamonds
default: self = .clubs
}
}
}
for i in 0..<Suit.count {
print(Suit(index: i).rawValue)
}
其他的解决方法都是可行的,但它们都假设了可能的等级和花色的数量,或者第一和最后的等级是什么。的确,在可预见的未来,一副纸牌的布局可能不会有太大变化。然而,一般来说,编写尽可能少假设的代码会更简洁。我的解决方案:
我已经在Suit枚举中添加了一个原始类型,所以我可以使用Suit(rawValue:)来访问Suit案例:
enum Suit: Int {
case Spades = 1
case Hearts, Diamonds, Clubs
func simpleDescription() -> String {
switch self {
case .Spades:
return "spades"
case .Hearts:
return "hearts"
case .Diamonds:
return "diamonds"
case .Clubs:
return "clubs"
}
}
func color() -> String {
switch self {
case .Spades:
return "black"
case .Clubs:
return "black"
case .Diamonds:
return "red"
case .Hearts:
return "red"
}
}
}
enum Rank: Int {
case Ace = 1
case Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten
case Jack, Queen, King
func simpleDescription() -> String {
switch self {
case .Ace:
return "ace"
case .Jack:
return "jack"
case .Queen:
return "queen"
case .King:
return "king"
default:
return String(self.rawValue)
}
}
}
在Card的createDeck()方法实现的下面。init(rawValue:)是一个可失败的初始化式,返回一个可选值。通过在两个while语句中展开并检查它的值,不需要假设Rank或Suit情况的数量:
struct Card {
var rank: Rank
var suit: Suit
func simpleDescription() -> String {
return "The \(rank.simpleDescription()) of \(suit.simpleDescription())"
}
func createDeck() -> [Card] {
var n = 1
var deck = [Card]()
while let rank = Rank(rawValue: n) {
var m = 1
while let suit = Suit(rawValue: m) {
deck.append(Card(rank: rank, suit: suit))
m += 1
}
n += 1
}
return deck
}
}
下面是如何调用createDeck方法:
let card = Card(rank: Rank.Ace, suit: Suit.Clubs)
let deck = card.createDeck()
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
}