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
它花了我一点,而不仅仅是一个方法在结构像swift书调用,但我在枚举中设置了下一个函数。我会使用一个协议,我不知道为什么,但有秩设置为int混乱。
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.toRaw())
}
}
mutating func next() -> Rank {
var rank = self
var rawrank = rank.toRaw()
var nrank: Rank = self
rawrank = rawrank + 1
if let newRank = Rank.fromRaw(rawrank) {
println("\(newRank.simpleDescription())")
nrank = newRank
} else {
return self
}
return nrank
}
}
enum Suit {
case Spades, Hearts, Diamonds, Clubs
func color() -> String {
switch self {
case .Spades, .Clubs:
return "black"
default:
return "red"
}
}
func simpleDescription() -> String {
switch self {
case .Spades:
return "spades"
case .Hearts:
return "hearts"
case .Diamonds:
return "diamonds"
case .Clubs:
return "clubs"
}
}
mutating func next() -> Suit {
switch self {
case .Spades:
return Hearts
case .Hearts:
return Diamonds
case .Diamonds:
return Clubs
case .Clubs:
return Spades
}
}
}
struct Card {
var rank: Rank
var suit: Suit
func deck() -> Card[] {
var tRank = self.rank
var tSuit = self.suit
let tcards = 52 // we start from 0
var cards: Card[] = []
for i in 0..tcards {
var card = Card(rank: tRank, suit: tSuit)
cards.append(card)
tRank = tRank.next()
tSuit = tSuit.next()
}
return cards
}
func simpleDescription() -> String {
return "The \(rank.simpleDescription()) of \(suit.simpleDescription())"
}
}
var card = Card(rank: .Ace, suit: .Spades)
var deck = card.deck()
我使用了一些常识,但这可以通过将花色乘以等级来轻松纠正(如果你没有使用标准的桥牌,你必须相应地改变枚举,如果基本上只是通过不同的枚举进行步骤)。为了节省时间,我使用了ranks rawValues,如果你愿意,你也可以为西装做同样的事情。然而,这个例子没有它,所以我决定在不改变suit rawValue的情况下找出它
其他回答
在Swift中,枚举类型可以像EnumType一样访问。案例:
let tableView = UITableView(frame: self.view. view)UITableViewStyle.Plain)
大多数情况下,只有当您有几个选项可以使用,并且确切地知道在每个选项上要做什么时,才会使用枚举类型。
在处理枚举类型时,使用for-in结构没有太大意义。
你可以这样做,例如:
func sumNumbers(numbers : Int...) -> Int {
var sum = 0
for number in numbers{
sum += number
}
return sum
}
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)
}
}
//...
}
对不起,我的回答是具体到我如何在我需要做的事情中使用这篇文章。对于那些无意中遇到这个问题的人,寻找一种方法在枚举中找到一个case,这是一种方法(Swift 2新增):
编辑:小写驼峰现在是Swift 3 enum值的标准
// From apple docs: If the raw-value type is specified as String and you don’t assign values to the cases explicitly, each unassigned case is implicitly assigned a string with the same text as the name of that case.
enum Theme: String
{
case white, blue, green, lavender, grey
}
func loadTheme(theme: String)
{
// this checks the string against the raw value of each enum case (note that the check could result in a nil value, since it's an optional, which is why we introduce the if/let block
if let testTheme = Theme(rawValue: theme)
{
// testTheme is guaranteed to have an enum value at this point
self.someOtherFunction(testTheme)
}
}
对于那些对枚举感到疑惑的人来说,本页上给出的答案包括一个包含所有枚举值的数组的静态var/let是正确的。最新的苹果tvOS示例代码包含了完全相同的技术。
也就是说,他们应该在语言中构建一个更方便的机制(苹果,你在听吗?)
enum Rank: Int {
...
static let ranks = (Rank.Ace.rawValue ... Rank.King.rawValue).map{Rank(rawValue: $0)! }
}
enum Suit {
...
static let suits = [Spades, Hearts, Diamonds, Clubs]
}
struct Card {
...
static func fullDesk() -> [Card] {
var desk: [Card] = []
for suit in Suit.suits {
for rank in Rank.ranks {
desk.append(Card(rank: rank,suit: suit))
}
}
return desk
}
}
这个怎么样?
枚举有toRaw()和fromRaw()方法。所以如果你的原始值是Int,你可以从第一个枚举迭代到最后一个枚举:
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"
}
}
}
for i in Suit.Spades.toRaw()...Suit.Clubs.toRaw() {
if let covertedSuit = Suit.fromRaw(i) {
let description = covertedSuit.simpleDescription()
}
}
一个问题是在运行simpleDescription方法之前需要测试可选值,因此我们首先将convertedSuit设置为我们的值,然后将常量设置为convertedSuit.simpleDescription()