SWIFT Enumeration(1)

Swift中定义Enumeration跟其它语言挺类似的，看如下定义一个星期的Enumeration

enum Day:Int{

case Monday = 1, Tuesday,Wednesday,Thursday,Friday,Saturday,Sunday

}

Monday赋值为1其它值则按顺序自动赋值，也是一种比较简便的写法，当然也可以为每个属性赋值

enum Day:Int{

case Monday = 1

case Tuesday = 2,

case Wednesday = 3,Thursday,Friday,Saturday,Sunday

}

let myday = Day.Sunday //自动推测为Day类型的Enumeration

let dayNumber = Day.Sunday.rawValue //值为7

以下定义一个String类型的Enumeration

enum Period:String{

case Morning = "Morning"

case Noon = "Noon"

case AfterNoon = "Afternoon"

case Night = "Night"

case MidNight = "MidNight"

}

Enumeration还有一个很强大的功能叫关值

enum AgeStatus{

case Legal

case NoOldEnought(Int)  //关联值

init(){

self = Legal //default value

}

var description:String{

switch self{

case Legal:

return "Age is legal"

case NoOldEnought(let a):

return "Age \(a) is illegal"

default:

return "Age is illegal"

}

}

}

var sheAgeStatus = AgeStatus()

sheAgeStatus.description  //Age is legal

sheAgeStatus = AgeStatus.NoOldEnought(10)

sheAgeStatus.description // return Age 10 is illegal

Enumeration中还可以定义方法，在上面添加以下方法代码：

func reportStatus() ->String{

return self.description

}

调用方法：

sheAgeStatus.reportStatus()