spark--transform算子--groupByKey

import org.apache.spark.{SparkConf, SparkContext}

/**
  * Created by liupeng on 2017/6/16.
  */
object T_groupByKey {

  System.setProperty("hadoop.home.dir","F:\\hadoop-2.6.5")

  def main(args: Array[String]): Unit = {
    val conf = new SparkConf().setAppName("groupByKey_test").setMaster("local")
    val sc = new SparkContext(conf)
    val scoreMap = List("liupeng" -> 150, "liupeng" -> 50, "liusi" -> 120, "xiaoma" -> 100)
    //groupByKey把相同的key的元素放到一起去
    val rdd = sc.parallelize(scoreMap)
    val result = rdd.groupByKey()
    result.foreach(x => println(x._1 + ":" + x._2))
  }
}

运行结果：

liusi:CompactBuffer(120)
liupeng:CompactBuffer(150, 50)
xiaoma:CompactBuffer(100)