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
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
}
其他回答
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
}
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
}
有时,您可能会处理具有底层原始整数类型的枚举类型,这种类型在整个软件开发生命周期中都会发生变化。下面是一个很适合这种情况的例子:
public class MyClassThatLoadsTexturesEtc
{
//...
// Colors used for gems and sectors.
public enum Color: Int
{
// Colors arranged in order of the spectrum.
case First = 0
case Red, Orange, Yellow, Green, Blue, Purple, Pink
// --> Add more colors here, between the first and last markers.
case Last
}
//...
public func preloadGems()
{
// Preload all gems.
for i in (Color.First.toRaw() + 1) ..< (Color.Last.toRaw())
{
let color = Color.fromRaw(i)!
loadColoredTextures(forKey: color)
}
}
//...
}
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)
}
}
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)")
}