【def函数+基础声明】

def 函数名称(参数列表):函数返回值类型=

def looper(x: Long, y: Long): Long = {
    var a = x
    var b = y
    while (a != 0) {
      val temp = a
      a = b % a
      b = temp
    }
    //返回值
    b
  }

若无返回值则返回值类型设置为Unit

def looper(x: Long, y: Long): Unit = {
    var a = x
    var b = y
    while (a != 0) {
      val temp = a
      a = b % a
      b = temp
    }
  }

数组声明

var z:Array[String] = new Array[String](3)
或
var z = new Array[String](3)
或
var z = Array("Runoob", "Baidu", "Google")

Collection声明

// 定义整型 List
val x = List(1,2,3,4)

// 定义 Set
val x = Set(1,3,5,7)

// 定义 Map
val x = Map("one" -> 1, "two" -> 2, "three" -> 3)

// 创建两个不同类型元素的元组
val x = (10, "Runoob")

// 定义 Option
val x:Option[Int] = Some(5)