match

package matchcase

object matchcase01 {
  def main(args: Array[String]): Unit = {
    println(getProvinceName(11))
    println(getProvinceName(42))
    println(getProvinceName(12))
  }

  def getProvinceName(code: Int): String = {
    code match {
      case 42 => "湖北"
      case 11 => "北京"
      case _ => "未知"
    }
  }
}

package matchcase

object matchcase02 {
  def main(args: Array[String]): Unit = {
    val xiaohong = (100, 100, 100)
    val xiaoming = (89, 98)

    getScore(xiaohong)
    getScore(xiaoming)
    getScore((1,2,3,4))
  }

  def getScore(score:Any):Unit = {
    score match {
      case (a,b,c) => println(s"元组中有三个元素: a = ${a} b = ${b} c = ${c}")
      case (a,b) => println(s"元组中有两个元素: a = ${a} b = ${b}")
      case _ => println("未知")
    }
  }
}

package matchcase

object matchcase03 {
  def main(args: Array[String]): Unit = {
    testType(1)
    testType(1.1)
    testType("1")
  }

  def testType(i:Any):Unit = {
    i match {
      case x:Int => println("当前变量是: Int")
      case x:Double => println("当前变量是: Double")
      case _ => println("未知")
    }
  }
}

package matchcase

object matchcase05 {
  // 定义一个样例类: 圆形。它有一个属性: 半径
  case class Circle(radius:Double)
  // 定义一个样例类: 矩形。它有两个属性: 长和宽
  case class Rectangle(width:Double,height:Double)

  // 定义一个方法，用来求圆形，矩形的面积
  def getArea(obj:Any):Unit = {
    obj match {
      case Circle(radius) => println("圆形的面积是: " + radius * radius * 3.14)
      case Rectangle(width,height) => println("矩形的面积是: " + width * height)
      case _ => println("未知")
    }
  }

  def main(args: Array[String]): Unit = {
    getArea(Circle(2))
    getArea(Rectangle(2,3))
    getArea("abc")
  }
}

package matchcase

object matchcase06 {
  def main(args: Array[String]): Unit = {
    val arr = Array(1,2,3,4,5)

    // 定义三个变量，分别设置初始值为arr的前三个元素的值？
    var a = arr(0)
    var b = arr(1)
    var c = arr(2)
    println("a = " + a + " b = " + b + " c = " + c)

    // 使用模式匹配，将arr的前三个元素分别赋值给a,b,c
    val Array(x,y,z,_*) = arr
    // _* 占位符，表示多的部分就放在这儿
    println("x = " + x + " y = " + y + " z = " + z)
  }
}

package matchcase

object matchcase07 {
  def main(args: Array[String]): Unit = {
    val a = 11

    a match {
      case x:Int if a > 10 => println("a 是大于10的Int")
      case _ => println("a is not Int")
    }
  }
}