模式匹配-判断星座

1.守卫语句的格式

* 知识点：守卫
* value match {
*    case 模式 if 条件 => 执行的事情
* }
 */
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")
    }
  }
}

2.案例-判断星座

/*
*
* 写一个函数，参数有两个。一个是月份，一个是日期。返回
* 1月20日到2月18日：水瓶座
 */
object matchcase08 {

  def getZodiac(month: Int, day: Int): String =
    month match {
      case 1 if day >= 20 => "水瓶座" //月份是1，并且 日期是>= 20的
      case 2 if day <= 18 => "水瓶座" //月份是2，并且 日期是<= 18的

      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 <= 20 => "双子座"

      case 6 if day >= 21 => "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 <= 22 => "天秤座"

      case 10 if day >= 23 => "天蝎座"
      case 11 if day <= 21 => "天蝎座"

      case 11 if day >= 22 => "射手座"
      case 12 if day <= 21 => "射手座"

      case 12 if day >= 22 => "摩羯座"
      case 1 if day <= 19 => "摩羯座"
      case _ => "未知"
    }

  def main(args: Array[String]): Unit = {

    println(getZodiac(1, 21))
    println(getZodiac(2, 20))
    println(getZodiac(3, 22))
    println(getZodiac(4, 20))
    println(getZodiac(5, 22))
    println(getZodiac(6, 21))
    println(getZodiac(7, 23))
    println(getZodiac(8, 23))
    println(getZodiac(9, 23))
    println(getZodiac(10, 24))
    println(getZodiac(11, 22))
    println(getZodiac(12, 22))


  }
}