Scala. Enumeration enumeration Example

Brief introduction

There is no enumeration type in Scala, but the enumeration class is provided in the standard class library to produce enumerations. After extending the enumeration class, call the value method to initialize the possible values in the enumeration.

The inner class value is actually an abstract class, and the real creation is Val. Because it's actually Val, you can pass in the ID and name for value

If not specified, the ID is added to the previous enumeration value ID, and name is the field name

Scala enumeration Example

Object trafficlightcolor extends enumeration {  type trafficlightcolor  = value  val red = value (0,  "Stop")   val yellow =  value (  val green = value) ("Go")}object margin extends  enumeration {  type margin = value  val top, bottom,  Left, right = value}import test. Trafficlightcolor._import test. Margin._object driver extends app {  println (bottom, bottom.id)    Def dowhat (Color: trafficlightcolor)  = {    if  (color ==  red)   "Stop"     else if  (color == yellow)   "hurry  Up  else  go   }  //use match match   def dowhat2 (color:  Trafficlightcolor)  = color match {    case red    =>  "Stop"     case  yellow =>  "Hurry up"     case _      = >  "Go"   }  // load Red  val red =  Trafficlightcolor (0)  // calls enumeration.apply   println (red, red.id)   println (Dowhat (red))   println (DOWHAT2 (trafficlightcolor.yellow))       //Print out all enumerations   margin.values.foreach { v => println (V,v.id)}}

Scala. Enumeration enumeration Example