构建列表

 

package main

object Test {

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

    //空列表
    val empty = List();
    println(empty); //List()

    val emptyList: List[Nothing] = List.empty;
    println(emptyList); //List()


    //构建列表
    val nums_1 = List(1, 2, 3);
    println(nums_1); //List(1, 2, 3)

    val numS_2 = 1 :: 2 :: 3 :: Nil;
    println(numS_2); //List(1, 2, 3)


    val L12 = List(1, 2);
    val L34 = 3 :: 4 :: Nil;

    val L1234 = L12 ::: L34; //2个列表拼接,返回一个新的列表
    println(L1234);
    //List(1, 2, 3, 4)


    val L134 = 1 :: L34;
    println(L134);
    //List(1, 3, 4)


    //返回列表下标为1的元素 -> L134[1]
    println(L134(1)); //3

  }

}