SWIFT Enumeration(2)

之前记录了Swift Enumeration(1)，这篇算是它的延续吧，继续说下Enumeration,看以下定义

enum TrainStatus {

    case OnTime

    case Delay(Int) //带关联值

}

var myTrainStatus = TrainStatus.Delay(10)

用Switch 匹配对象

switch myTrainStatus{

case .OnTime:

    println("Train is ontime")

case .Delay(let minutes): 

    println("Train delays \(minutes) minutes")

}

匹配方式是有先后顺序的，上面中先匹配到Delay然后再给里面的minutes赋值，好下面我将演示区间匹配。

switch myTrainStatus{

case .OnTime://匹配准时

    println("Train is ontime")

case .Delay(1...5)://匹配1到5

    println("Train delays less than five minutes")

case .Delay(6...10)://匹配6到10

    println("Train delays between six and ten minutes")

case .Delay(_): //匹配其它，里面是下划线

    println("Train delays more than ten minutes")

}

关联值的另一个例子，

enum Barcode{
    case UPCA(Int,Int,Int,Int)
    case QRCode(String)
}

var productCodeA:Barcode = Barcode.UPCA(10, 20, 30, 40)
var productCodeB:Barcode = Barcode.QRCode("This is an infomation")

switch productCodeB{
case .UPCA(let a,let b,let c,let d):
    print("\(a)-\(b)-\(c)-\(d)")
case .QRCode(let code):
    print("\(code)")
}