模式匹配-判断星座

守卫语句的格式

格式：value match {     case pattern if guardCondition => result     // 其他case语句... }

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 x: Int => println("a是Int，但不大于10")
      case _ => println("a不是Int类型")
    }
  }
}

案例-判断星座

package matchcase

object matchcase0 {
  def getZodiac(month: Int, day: Int): String = {
    (month, day) match {
      case 1 if day >= 20 => "水瓶座"
      case 2 if day <= 18 => "水瓶座"
      case 2 if day >= 19 => "双鱼座"
      case 3 if day <= 20 => "双鱼座"
      case 3 if day >= 21 => "白羊座"
      case 4 if day <= 19 => "白羊座"
      case 4 if day >= 20 => "金牛座"
      case 5 if day <= 20 => "金牛座"
      case 5 if day >= 21 => "双子座"
      case 6 if day <= 21 => "双子座"
      case 6 if day >= 22 => "巨蟹座"
      case 7 if day <= 22 => "巨蟹座"
      case 7 if day >= 23 => "狮子座"
      case 8 if day <= 22 => "狮子座"
      case 8 if day >= 23 => "处女座"
      case 9 if day <= 22 => "处女座"
      case 9 if day >= 23 => "天秤座"
      case 10 if day <= 23 => "天秤座"
      case 10 if day >= 24 => "天蝎座"
      case 11 if day <= 22 => "天蝎座"
      case 11 if day >= 23 => "射手座"
      case 12 if day <= 21 => "射手座"
      case 12 if day >= 22 => "摩羯座"
      case 1 if day <= 18 => "摩羯座"
      case _ => "未知"
    }
  }

  def main(args: Array[String]): Unit = {
    println(getZodiac(1, 19))
    println(getZodiac(1, 21))
    println(getZodiac(2, 19))
    println(getZodiac(11, 23))
    println(getZodiac(12, 25))
    println(getZodiac(13, 5))
  }
}