scala中Nil用法

http://www.runoob.com/scala/scala-lists.html

即Nil是空List

双冒号是追加进入

package com.yjsj.spark

object scala_test {
  def main(args: Array[String]): Unit = {
    val site = "Runoob" :: ("Google" :: ("Baidu" :: Nil))
    val site2: List[String] = site
    site.foreach(println)
    val nums = 1 :: (2 :: (3 :: (4 :: Nil)))
    val nums2: List[Int] = nums
    nums.foreach(println)

    // 二维列表
    val dim = (1 :: (0 :: (0 :: Nil))) ::
      (0 :: (1 :: (0 :: Nil))) ::
      (0 :: (0 :: (1 :: Nil))) :: Nil

    val dim2: List[List[Int]] = dim
    dim.foreach(println)
  }
}