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
我添加了函数count(),并迭代值:
public enum MetricType: Int {
case mvps = 0
case allNBA = 1
case championshipRings = 2
case finalAppearances = 3
case gamesPlayed = 4
case ppg = 5
static func count() -> Int {
return (ppg.rawValue) + 1
}
static var allValues: [MetricType] {
var array: [MetricType] = Array()
var item : MetricType = MetricType.mvps
while item.rawValue < MetricType.count() {
array.append(item)
item = MetricType(rawValue: (item.rawValue + 1))!
}
return array
}
}
其他回答
在Swift 3中,当底层枚举有rawValue时,你可以实现Strideable协议。优点是不像其他建议那样创建值数组,并且标准的Swift“for in”循环工作,这是一个很好的语法。
// "Int" to get rawValue, and Strideable so we can iterate
enum MyColorEnum: Int, Strideable {
case Red
case Green
case Blue
case Black
// required by Strideable
typealias Stride = Int
func advanced(by n:Stride) -> MyColorEnum {
var next = self.rawValue + n
if next > MyColorEnum.Black.rawValue {
next = MyColorEnum.Black.rawValue
}
return MyColorEnum(rawValue: next)!
}
func distance(to other: MyColorEnum) -> Int {
return other.rawValue - self.rawValue
}
// just for printing
func simpleDescription() -> String {
switch self {
case .Red: return "Red"
case .Green: return "Green"
case .Blue: return "Blue"
case .Black: return "Black"
}
}
}
// this is how you use it:
for i in MyColorEnum.Red ... MyColorEnum.Black {
print("ENUM: \(i)")
}
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)
}
}
您可以通过实现ForwardIndexType协议来迭代枚举。
ForwardIndexType协议要求您定义一个继任者()函数来逐级遍历元素。
enum Rank: Int, ForwardIndexType {
case Ace = 1
case Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten
case Jack, Queen, King
// ... other functions
// Option 1 - Figure it out by hand
func successor() -> Rank {
switch self {
case .Ace:
return .Two
case .Two:
return .Three
// ... etc.
default:
return .King
}
}
// Option 2 - Define an operator!
func successor() -> Rank {
return self + 1
}
}
// NOTE: The operator is defined OUTSIDE the class
func + (left: Rank, right: Int) -> Rank {
// I'm using to/from raw here, but again, you can use a case statement
// or whatever else you can think of
return left == .King ? .King : Rank(rawValue: left.rawValue + right)!
}
在开或闭范围内迭代(..<或…)将在内部调用继任者()函数,允许你这样写:
// Under the covers, successor(Rank.King) and successor(Rank.Ace) are called to establish limits
for r in Rank.Ace...Rank.King {
// Do something useful
}
enum Rank: Int
{
case Ace = 0
case Two, Three, Four, Five, Six, Seve, Eight, Nine, Ten
case Jack, Queen, King
case Count
}
enum Suit : Int
{
case Spades = 0
case Hearts, Diamonds, Clubs
case Count
}
struct Card
{
var rank:Rank
var suit:Suit
}
class Test
{
func makeDeck() -> Card[]
{
let suitsCount:Int = Suit.Count.toRaw()
let rankCount:Int = Rank.Count.toRaw()
let repeatedCard:Card = Card(rank:Rank.Ace, suit:Suit.Spades)
let deck:Card[] = Card[](count:suitsCount*rankCount, repeatedValue:repeatedCard)
for i:Int in 0..rankCount
{
for j:Int in 0..suitsCount
{
deck[i*suitsCount+j] = Card(rank: Rank.fromRaw(i)!, suit: Suit.fromRaw(j)!)
}
}
return deck
}
}
根据Rick的回答:这要快5倍
你可以试着像这样列举
enum Planet: String {
case Mercury
case Venus
case Earth
case Mars
static var enumerate: [Planet] {
var a: [Planet] = []
switch Planet.Mercury {
case .Mercury: a.append(.Mercury); fallthrough
case .Venus: a.append(.Venus); fallthrough
case .Earth: a.append(.Earth); fallthrough
case .Mars: a.append(.Mars)
}
return a
}
}
Planet.enumerate // [Mercury, Venus, Earth, Mars]