第五章_Spark核心编程_Rdd_行动算子_takeOrdered

1.定义

  /*
* 1.定义
*     def takeOrdered(num: Int)(implicit ord: Ordering[T]): Array[T]
* 2.功能
*     返回该 RDD 排序后的前 n 个元素组成的数组
* 3.note
*     1.默认为正序排序
*     逆序排序: Ordering.Int.reverse
*
* */

2.示例

  object takeOrderedTest extends App {

    val sparkconf: SparkConf = new SparkConf().setMaster("local").setAppName("distinctTest")

    val sc: SparkContext = new SparkContext(sparkconf)

    private val rdd: RDD[Int] = sc.makeRDD(List(8, 2, 4, 2), 4)

    private val result = rdd.takeOrdered(3)
    private val result1 = rdd.takeOrdered(3)(Ordering.Int.reverse)

    println(result.mkString(","))
    println(result1.mkString(","))

    sc.stop()
  }