Spark常用transformation算子操作 —— Scala版

阳光穿透心脏的1/2处 2022-05-19 07:23 267阅读 0赞

*  ### cartesian算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * 笛卡尔积 cartesian 算子
      * Created by asus on 2018/7/15.
      */
    object CartesianDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("CartesianDemo") ;
        conf.setMaster("local[2]") ;
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val classOne = List("lao wang" , "lao zhang" , "lao li" , "lao zhao")
        val classTwo = List("xiao wang" , "xiao zhao" , "xiao zhang" , "xiao li")
    
        val classOneRDD = sc.parallelize(classOne , 2)
        val classTwoRDD = sc.parallelize(classTwo , 2)
    
        val classOneCartesianTwoRDD = classOneRDD.cartesian(classTwoRDD)
        classOneCartesianTwoRDD.foreach{
          s => {
            println("( " + s._1 + " , " + s._2 + " )")
          }
        }
        sc.stop()
      }
    
    }

*  ### coalesce算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/6/16.
      * transformation 算子 coalesce(partitionNum : Int , shuffle : Boolean = false)
      * 默认参数是否进行shuffle为false，即只在本机进行partition合并，不同过网络传输
      */
    object CoalesceDemo {
      def main(args : Array[String]):Unit = {
        val conf = new SparkConf()
        conf.setAppName("CoalesceDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
        val sc = new SparkContext(conf)
    
        val numbers = Array(1 to 100 : _*)
        val numRdd = sc.parallelize(numbers , 10)
    
        // 输出当前RDD中数据所属的partition编号
        // scala 中匿名函数中 {} 与 () 的区别就是{} 是代码块 () 只能是一行语句
        val numRddWithPartitionIndex = numRdd.mapPartitionsWithIndex{
          (index , numIter) => {
            var numString = List[String]()
            while(numIter.hasNext) {
              val num = numIter.next
              numString = List("number " + num + " with partition index " + index) ::: numString
            }
            numString.iterator
          }
        }
        numRddWithPartitionIndex.collect().foreach(println)
    
        // 努力将RDD中partition减少为5个，不进行shuffle
        val coalescedNumRdd = numRdd.coalesce(5)
    
        // 输出coalesce之后RDD中数据所属的partition index 编号
        val coalescedNumRddWithPartitionIndex = coalescedNumRdd.mapPartitionsWithIndex{
          (index , numIter) => {
            var numString = List[String]()
            while(numIter.hasNext) {
              val num = numIter.next()
              numString = List("number " + num + " with partition index " + index) ::: numString
            }
            numString.iterator
          }
        }
        coalescedNumRddWithPartitionIndex.collect().foreach(println)
    
        sc.stop()
      }
    }

*  ### cogroup算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/7/18.
      */
    object CogroupDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("CogroupDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
    
        val scores_1 = List(("lao wang" , 10) , ("lao zhang" , 20) , ("lao zhao" , 30) , ("lao li" , 40))
        val scores_2 = List(("lao wang" , 10) , ("xiao zhang" , 20) , ("lao zhao" , 30) , ("xiao li" , 40))
    
        val scoreOneRDD = sc.parallelize(scores_1 , 2)
        val scoreTwoRDD = sc.parallelize(scores_2 , 2)
    
        val cogroupRDD = scoreOneRDD.cogroup(scoreTwoRDD)
    
        cogroupRDD.foreach(println)
    
        sc.stop()
      }
    }

*  ### distinct算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * distinct RDD 去重算子，有shuffle
      * Created by asus on 2018/7/11.
      */
    object DistinctDemo {
      def main(args :Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("DistinctDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val names = List("lao wang" , "lao li" , "lao zhang" , "lao zhao" , "lao wang" , "lao li" , "lao zhang" , "lao zhao")
    
        val nameRDD = sc.parallelize(names , 4)
        nameRDD.mapPartitionsWithIndex{
          (index , names) => {
            var nameWithIndex = List[String]()
            while(names.hasNext) {
              val name = names.next()
              nameWithIndex = List("name " + name + " with index " + index) ::: nameWithIndex
            }
            nameWithIndex.iterator
          }
        }.foreach(println)
    
        val distinctNameRDD = nameRDD.distinct()
        distinctNameRDD.mapPartitionsWithIndex{
          (index , names) => {
            var nameWithIndex = List[String]()
            while(names.hasNext) {
              val name = names.next()
              nameWithIndex = List("name " + name + " with index " + index) ::: nameWithIndex
            }
            nameWithIndex.iterator
          }
        }.foreach(println)
    
        sc.stop()
    
      }
    
    }

*  ### filter算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/6/16.
      * transformation 算子 filter(f : U => bool)
      * 只保留 f 返回 为true的元素
      * filter算子通常与coalesce算子一起使用，进行partition合并，减少partition的数量，缓解filter造成的数据倾斜
      */
    object FilterDemo {
      def main(args : Array[String]):Unit = {
        val conf = new SparkConf()
        conf.setAppName("FilterDemo")
        conf.setMaster("local[2]")
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val numbers = Array(1 to 10 : _*)
        val numRdd = sc.parallelize(numbers)
    
        val numLarger5 = numRdd.filter(n => n > 5)
    
        def printNumber(n : Int) : Unit = {
          println("number : " + n)
        }
    
        numRdd.foreach(printNumber)
        numLarger5.foreach(printNumber)
    
        sc.stop
      }
    
    }

*  ### flatMap算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/6/16.
      * transformation 算子 flatMap(f : U => U)
      * 先执行map 然后进行 flat 进行扁平化
      */
    object FlatMapDemo {
      def main(args : Array[String]):Unit = {
        val conf = new SparkConf()
        conf.setAppName("FlatMapDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
        val sc = new SparkContext(conf)
    
        val sentences = Array("today is a nice day" , "i love you" , "who am i")
        val sentenceRdd = sc.parallelize(sentences , 2)
        sentenceRdd.collect().foreach(println)
    
        val wordRdd = sentenceRdd.flatMap(s => s.split(" "))
        wordRdd.collect().foreach(println)
    
        sc.stop()
      }
    }

*  ### groupByKey算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/6/17.
      * transformation 算子 groupByKey (k , v) => (k , Itarable(V1 , V2 , ...))
      * 产生shuffle
      */
    object GroupByKeyDemo {
    
      def main(args : Array[String]): Unit = {
        val conf = new SparkConf()
        conf.setAppName("GroupByKeyDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
        val sc = new SparkContext(conf)
    
        val userInfo = List(("zhang" , 100) , ("wang" , 90) , ("li" , 80) ,
                            ("zhang" , 101) , ("wang" , 91) , ("li" , 81) ,
                            ("zhang" , 102) , ("wang" , 92) , ("li" , 82))
        val userRdd = sc.parallelize(userInfo)
        userRdd.foreach(println)
    
        userRdd.reduceByKey(_ + _).collect().foreach(println)
    
        // 按照key 进行分组
        val userRddGroupByKey = userRdd.groupByKey()
        userRddGroupByKey.foreach(println)
    
        // 计算每个分组score的总数
        val userTotalScore = userRddGroupByKey.map{
          t => {
            var sum = 0
            for(s <- t._2) {
              sum += s
            }
            (t._1 , sum)
          }
        }
        userTotalScore.collect().foreach(println)
    
        sc.stop()
      }
    
    }

*  ### intersection算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * RDD 求交集 intersection 算子
      * Created by asus on 2018/7/15.
      */
    object IntersectionDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("IntersectionDemoJava") ;
        conf.setMaster("local[2]") ;
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val classOne = List("lao wang" , "lao wang" , "lao zhang" , "lao li" , "lao zhao")
        val classTwo = List("lao wang" , "lao wang" , "lao zhao" , "lao zhao" , "xiao wang" , "xiao zhao")
    
        val classOneRDD = sc.parallelize(classOne , 2)
        val classTwoRDD = sc.parallelize(classTwo , 2)
    
        val classOneAndTwoRDD = classOneRDD.intersection(classTwoRDD)
        classOneAndTwoRDD.foreach {
          s => {
            println(s)
          }
        }
    
        sc.stop()
      }
    
    }

*  ### join算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/7/18.
      */
    object JoinDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("CogroupDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
    
        val scores_1 = List(("lao wang" , 10) , ("lao zhang" , 20) , ("lao zhao" , 30) , ("lao li" , 40))
        val scores_2 = List(("lao wang" , 10) , ("xiao zhang" , 20) , ("lao zhao" , 30) , ("xiao li" , 40))
    
        val scoreOneRDD = sc.parallelize(scores_1 , 2)
        val scoreTwoRDD = sc.parallelize(scores_2 , 2)
    
        val joinRDD = scoreOneRDD.join(scoreTwoRDD)
    
        joinRDD.foreach{
          t => {
            println(t._1 + " -> " + t._2._1 + " , " + t._2._2)
          }
        }
    
        sc.stop()
      }
    
    }

*  ### mapPartitions算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/6/16.
      * transformation 算子 mapPartitions(f : Iterator[T] => Iterator[U])
      * 将 f 以 Partiotions分区为单位，应用于整个partitions，其作用与map算子相同，在RDD中数据量较小的情况下可以提升执行速度
      * 数据量大会导致内存溢出 OOM
      */
    object MapPartitionsDemo {
      def main(args : Array[String]):Unit = {
        println("MapPartitionsDemoScala")
    
        val conf = new SparkConf()
        conf.setAppName("MapPartitionsDemoScala")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val names = List[String]("xuruyun" , "liangjingru" , "wangfei")
    
        val scoreMap = Map("xuruyun" -> 150 , "liangjingru" -> 100 , "wangfei" -> 90)
    
        val nameRdd = sc.parallelize(names)
    
        /**
          * 自定义mapPartitions的处理方法 Iterator[String] => Iterator[Int]
          * @param names
          * @return
          */
        def getUserScore(names: Iterator[String]) : Iterator[Int] = {
          var userScore = List[Int]()
          while(names.hasNext) {
            val name = names.next()
            val score = scoreMap(name)
            userScore = List(score) ::: userScore
          }
          userScore.iterator
        }
        // 自定义打印方法
        def printScore(score : Int) {println("score ：" + score)}
    
        val scoreRdd = nameRdd.mapPartitions(getUserScore)
        scoreRdd.foreach(printScore)
        sc.stop()
      }
    
    
    }

*  ### mapPartitionsWithIndex算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/6/16.
      * transformation 算子 mapPartitionsWithIndex(f : (Integer , INtorator[U]) => Intorator[T])
      * 该算子与map、mapPartitions算子类似，知识多带了一个partitions的编号
      */
    object MapPartitionsWithIndexDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("MapPartitionsWithIndexDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val names = Array("xuruyun" , "liangjingru" , "wangfei")
        val nameRdd = sc.parallelize(names)
    
        def getNamePartitionIndex(index: Int , names : Iterator[String]) : Iterator[String] = {
          var newNames = List[String]()
          while(names.hasNext) {
            val name = names.next()
            newNames = List("Hello " + name + " with index " + index) ::: newNames
          }
          newNames.iterator
        }
    
        val nameRddWithPartitionsIndex = nameRdd.mapPartitionsWithIndex(getNamePartitionIndex)
        nameRddWithPartitionsIndex.foreach(println)
        sc.stop()
      }
    
    }

*  ### map算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/5/20.
      * transformation 算子 map(f : U => U)
      * 将 f 应用与 RDD的每个元素
      */
    object MapRddDemo {
      def printNum(num : Int) : Unit = println(num)
    
      def main(args: Array[String]): Unit = {
        println(args)
    
        val conf = new SparkConf().setAppName("map rdd demo").setMaster("local[2]")
        System.setProperty("hadoop.home.dir", "E:\\hadoop-2.6.0")
        val sc = new SparkContext(conf)
    
        val numRdd = sc.parallelize(Array(1 , 2 , 3 , 4))
    
        numRdd.map(num => num + 1).foreach(num => printNum(num))
        val sum = numRdd.reduce(_ + _)
        println("sum = " + sum)
        sc.stop()
      }
    }

*  ### repartition算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/6/16.
      * transformation 算子 repartition(num)
      * 用于提高并行度 ， 会进行shuffle <==> coalesce(num , true)
      * 建议：减少partition数量使用coalsece算子，增加partition数量使用repartition算子
      * 产生shuffle
      */
    object RepartitionDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("RepartitionDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
        val sc = new SparkContext(conf)
    
        val numbers = Array(1 to 100 : _*)
        val numRdd = sc.parallelize(numbers , 10)
    
        val numRddWithPartitionIndex = numRdd.mapPartitionsWithIndex{
          (index , numIter) => {
            var numString = List[String]()
            while(numIter.hasNext) {
              val num = numIter.next()
              numString = List("number " + num + "with partition index " + index) ::: numString
            }
            numString.iterator
          }
        }
        numRddWithPartitionIndex.collect().foreach(println)
    
        val numRddRepartition = numRdd.repartition(5)
    
        val numRddRepartitionWithPartitionIndex = numRddRepartition.mapPartitionsWithIndex{
          (index , numIter) => {
            var numString = List[String]()
            while(numIter.hasNext) {
              val num = numIter.next()
              numString = List("number " + num + "with partition index " + index) ::: numString
            }
            numString.iterator
          }
        }
        numRddRepartitionWithPartitionIndex.collect().foreach(println)
    
        sc.stop()
      }
    }

*  ### sample算子 ###

package rddDemo.transformation
    
    import org.apache.spark.SparkConf
    import org.apache.spark.SparkContext
    
    /**
      * sample(replace:boolean , fraction:float , seed : long) 取样算子
      * Created by asus on 2018/7/8.
      */
    object SampleDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("SampleDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val names = List("lao wang" , "xiao wang" , "lao zhang" , "xiao zhang" , "lao li" , "xiao li")
        val namesRDD = sc.parallelize(names , 3)
    
        // 无放回取样50%
        println(">>>>>>>>>>>>>>>>>> 无放回取样50% <<<<<<<<<<<<<<<<<")
        namesRDD.sample(false , 0.5).foreach(println)
    
        // 有放回取样50%
        println(">>>>>>>>>>>>>>>>>> 有放回取样50% <<<<<<<<<<<<<<<<<")
        namesRDD.sample(true , 0.5).foreach(println)
    
        // 无放回取样50%，指定seed，取样唯一
        println(">>>>>>>>>>>>>>>>>> 无放回取样50%，指定seed，取样唯一 <<<<<<<<<<<<<<<<<")
        namesRDD.sample(false , 0.5 , 100).foreach(println)
    
        // 有放回取样50%，指定seed，取样唯一
        println(">>>>>>>>>>>>>>>>>> 有放回取样50%，指定seed，取样唯一 <<<<<<<<<<<<<<<<<")
        namesRDD.sample(true , 0.5 , 100).foreach(println)
    
        sc.stop()
      }
    }

*  ### sortByKey算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/7/11.
      */
    object SortByKeyDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("SortByKeyDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" ,"E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val scores = List[(String , Integer)](("lao wang" , 10) , ("lao zhang" , 20) , ("lao li" , 30) , ("lao zhao" , 40))
        val scoreRDD = sc.parallelize(scores , 2)
        scoreRDD.foreach{
          s => {
            println("name -> " + s._1 + " , score -> " + s._2)
          }
        }
    
        // 升序
        println(">>>>>>>>>>>>>>>>>>>>>>>>>>> asc(升序) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<")
       val scoreSortByKeyAscRDD = scoreRDD.sortByKey(true)
        scoreSortByKeyAscRDD.foreach{
          s => {
            println("name -> " + s._1 + " , score -> " + s._2)
          }
        }
    
        // 降序
        println(">>>>>>>>>>>>>>>>>>>>>>>>>>> desc(降序) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<")
        val scoreSortByKeyDescRDD = scoreRDD.sortByKey(true)
        scoreSortByKeyDescRDD.foreach{
          s => {
            println("name -> " + s._1 + " , score -> " + s._2)
          }
        }
    
        // 按照分数升序排序
        println(">>>>>>>>>>>>>>>>>>>>>>>>>>> asc(按照分数升序排序) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<")
        val scoreAscRDD = scoreRDD.map(s => (s._2 , s._1)).sortByKey(true).map(s => (s._2 , s._1)).foreach{
          s => {
            println("name -> " + s._1 + " , score -> " + s._2)
          }
        }
    
        // 按照分数降序排序
        println(">>>>>>>>>>>>>>>>>>>>>>>>>>> desc(按照分数降序排序) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<")
        val scoreDescRDD = scoreRDD.map(s => (s._2 , s._1)).sortByKey(false).map(s => (s._2 , s._1)).foreach{
          s => {
            println("name -> " + s._1 + " , score -> " + s._2)
          }
        }
    
        sc.stop()
      }
    
    }

*  ### union算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * rdd_1.union(rdd_2)
      * 直接合并RDD的partition
      * 如果rdd_1，rdd_2分别有两个partition，则合并后的RDD有4个partition，即union过程中不会shuffle
      * Created by asus on 2018/7/8.
      */
    object UnionDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("UnionDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val oldMan = List("lao wang" , "lao zhang" , "lao li" , "lao zhao")
        val youngMan = List("xiao wang" , "xiao zhang" , "xiao li" , "xiao zhao")
    
        /**
          * name : lao li with index 1
          * name : lao zhao with index 1
          * name : lao wang with index 0
          * name : lao zhang with index 0
          */
        // oldManRDD 有两个 partition
        val oldManRDD = sc.parallelize(oldMan , 2)
        val oldManWithIndex = oldManRDD.mapPartitionsWithIndex{
          (index , names) => {
            var nameWithIndex = List[String]()
            while(names.hasNext) {
              nameWithIndex = List("name : " + names.next() + " with index " + index) ::: nameWithIndex
            }
            nameWithIndex.iterator
          }
        }
        oldManWithIndex.foreach(println)
    
        /**
          * name : xiao li with index 1
          * name : xiao zhao with index 1
          * name : xiao wang with index 0
          * name : xiao zhang with index 0
          */
        // youngManRDD 有两个 partition
        val youngManRDD = sc.parallelize(youngMan , 2)
        val youngManRDDWithIndex = youngManRDD.mapPartitionsWithIndex{
          (index , names) => {
            var nameWithIndex = List[String]()
            while(names.hasNext) {
              nameWithIndex = List("name : " + names.next() + " with index " + index) ::: nameWithIndex
            }
            nameWithIndex.iterator
          }
        }
        youngManRDDWithIndex.foreach(println)
    
        /**
          * name : lao li with index 1
          * name : lao zhao with index 1
          * name : xiao wang with index 2
          * name : xiao zhang with index 2
          * name : xiao li with index 3
          * name : xiao zhao with index 3
          * name : lao wang with index 0
          * name : lao zhang with index 0
          */
        // 合并 oldManRDD 和 youngManRDD , 合并后的RDD中有 4 个 partition，且每个partition 中的内容与未合并前一样
        val unionOldAndYoungRDD = oldManRDD.union(youngManRDD)
        val unionOldAndYoungRDDWithIndex = unionOldAndYoungRDD.mapPartitionsWithIndex{
          (index , names) => {
            var nameWithIndex = List[String]()
            while(names.hasNext) {
              nameWithIndex = List("name : " + names.next() + " with index " + index) ::: nameWithIndex
            }
            nameWithIndex.iterator
          }
        }
        unionOldAndYoungRDDWithIndex.foreach(println)
    
        sc.stop()
      }
    
    }

*  ### saveAsTextFile算子 ###

package rddDemo.transformation
    
    import org.apache.spark.{SparkConf, SparkContext}
    
    /**
      * Created by asus on 2018/7/15.
      */
    object SaveAsTextFileDemo {
      def main(args : Array[String]) : Unit = {
        val conf = new SparkConf()
        conf.setAppName("SaveAsTextFileDemo")
        conf.setMaster("local[2]")
    
        System.setProperty("hadoop.home.dir" , "E:\\hadoop-2.6.0")
    
        val sc = new SparkContext(conf)
    
        val numbers = Array(1 to 10 : _*)
    
        val numberRDD = sc.parallelize(numbers , 2)
    
        // 将数据文件保存到本地文件系统（前提事目录不能事先存在）
        numberRDD.saveAsTextFile("src/main/scala/rddDemo/saveAsTextFilePath")
        // 将数据文件保存到HDFS（前提事目录不能事先存在）
    //    numberRDD.saveAsTextFile("hdfs://ip:9000/saveAsTextFilePath")
        sc.stop()
      }
    
    }