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
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)
}
}
//...
}
其他回答
我使用了下面的方法,假设我知道哪个是Rank enum中的最后一个值,所有的Rank在Ace之后都有增量值
我喜欢这种方式,因为它干净,小,容易理解
func cardDeck() -> Card[] {
var cards: Card[] = []
let minRank = Rank.Ace.toRaw()
let maxRank = Rank.King.toRaw()
for rank in minRank...maxRank {
if var convertedRank: Rank = Rank.fromRaw(rank) {
cards.append(Card(rank: convertedRank, suite: Suite.Clubs))
cards.append(Card(rank: convertedRank, suite: Suite.Diamonds))
cards.append(Card(rank: convertedRank, suite: Suite.Hearts))
cards.append(Card(rank: convertedRank, suite: Suite.Spades))
}
}
return cards
}
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
}
实验内容是: 实验
在Card中添加一个方法,用于创建一副完整的牌,每一副牌都是rank和花色的组合。
因此,除了添加方法之外,没有修改或增强给定的代码(并且没有使用还没有教过的东西),我想出了这个解决方案:
struct Card {
var rank: Rank
var suit: Suit
func simpleDescription() -> String {
return "The \(rank.simpleDescription()) of \(suit.simpleDescription())"
}
func createDeck() -> [Card] {
var deck: [Card] = []
for rank in Rank.Ace.rawValue...Rank.King.rawValue {
for suit in Suit.Spades.rawValue...Suit.Clubs.rawValue {
let card = Card(rank: Rank(rawValue: rank)!, suit: Suit(rawValue: suit)!)
//println(card.simpleDescription())
deck += [card]
}
}
return deck
}
}
let threeOfSpades = Card(rank: .Three, suit: .Spades)
let threeOfSpadesDescription = threeOfSpades.simpleDescription()
let deck = threeOfSpades.createDeck()
原则上,如果你不为enum的大小写使用原始值赋值,这样做是可能的:
enum RankEnum: Int {
case Ace
case One
case Two
}
class RankEnumGenerator: Generator {
var i = 0
typealias Element = RankEnum
func next() -> Element? {
let r = RankEnum.fromRaw(i)
i += 1
return r
}
}
extension RankEnum {
static func enumerate() -> SequenceOf<RankEnum> {
return SequenceOf<RankEnum>({ RankEnumGenerator() })
}
}
for r in RankEnum.enumerate() {
println("\(r.toRaw())")
}
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())
}
}
}
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, .Clubs: return "black"
case .Hearts, .Diamonds: return "red"
}
}
}
struct Card {
var rank: Rank
var suit: Suit
func simpleDescription() -> String {
return "The \(rank.simpleDescription()) of \(suit.simpleDescription())"
}
static func createPokers() -> Card[] {
let ranks = Array(Rank.Ace.toRaw()...Rank.King.toRaw())
let suits = Array(Suit.Spades.toRaw()...Suit.Clubs.toRaw())
let cards = suits.reduce(Card[]()) { (tempCards, suit) in
tempCards + ranks.map { rank in
Card(rank: Rank.fromRaw(rank)!, suit: Suit.fromRaw(suit)!)
}
}
return cards
}
}