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1.定义语法:
2.使用 enum CompassPoint { case North case South case East case West } var directionToHead = CompassPoint.West directionToHead = .South switch directionToHead { case .North: println("Lots of planets have a north") case .South: println("Watch out for penguins") case .East: println("Where the sun rises") default: println("Nothing") } 注:1.变量一个次赋值为枚举类型以后,第二次赋值可以使用点语法省略,即.South 2.switch中必须覆盖所有的枚举类型,如果太多,可使用default
3.相关值(Associated Values) swift语句中可以储存任何类型的相关值 enum Chazidian { case Pianpang(String, String) case Zimu(String) case Bihua(Int) } var c1 = Chazidian.Pianpang("一","田") var c2 = Chazidian.Zimu("a") var c3 = Chazidian.Bihua(3) switch c3 { case .Pianpang(let s1, let s2): println("偏旁:\(s1),\(s2)") case .Zimu(let s3): println("字母:\(s3)") case .Bihua(let s4): println("笔画:\(s4)") } //笔画:3
3.默认值 swift中枚举的默认值需要自己手动添加: //方式1:对每一个做赋值 enum ASCIIControlCharacter: Character { case Tab = "\t" case LineFeed = "\n" case CarriageReturn = "\r" } //方式2:自动递增 enum Planet: Int { case Mercury = 1, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune }
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