1.map

一条一条读取

def map(): Unit ={

    val list = List("张无忌", "赵敏", "周芷若")

    val listRDD = sc.parallelize(list)

    val nameRDD = listRDD.map(name => "Hello " + name)

    nameRDD.foreach(name => println(name))

  }

2.flatMap

扁平化

def flatMap(): Unit ={

    val list = List("张无忌 赵敏","宋青书 周芷若")

    val listRDD = sc.parallelize(list)

    val nameRDD = listRDD.flatMap(line => line.split(" ")).map(name => "Hello " + name)

    nameRDD.foreach(name => println(name))

  }

3.mapPartitions

一次读取一个分区数据

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(1, 2, 3, 4, 5, 6)

    val rdd = spark.parallelize(list, 2)

    rdd.foreach(println)

    val rdd2 = rdd.mapPartitions(iterator => {

      val newList = new ListBuffer[String]

      while (iterator.hasNext) {

        newList.append("hello" + iterator.next())

      }

      newList.toIterator

    })

    rdd2.foreach(name => println(name))

  }

}

4.mapPartitionsWithIndex

一次读取一个分区数据，并且知道是哪个分区的

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(1, 2, 3, 4, 5, 6)

    val rdd = spark.parallelize(list, 2)

    val rdd2 = rdd.mapPartitionsWithIndex((index, iterator) => {

      val newList = new ListBuffer[String]

      while (iterator.hasNext) {

        newList.append(index + "_" + iterator.next())

      }

      newList.toIterator

    })

    rdd2.foreach(name => println(name))

  }

}

5.reduce

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(1, 2, 3, 4, 5, 6)

    val rdd = spark.parallelize(list)

    val result = rdd.reduce((x, y) => x + y)

    println(result)

  }

}

6.reduceBykey

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(("武当", 99), ("少林", 97), ("武当", 89), ("少林", 77))

    val rdd = spark.parallelize(list)

    val rdd2 = rdd.reduceByKey(_ + _)

    rdd2.foreach(tuple => println(tuple._1 + ":" + tuple._2))

  }

}

7.union

合并，但不去重

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list1 = List(1,2,3,4)

    val list2 = List(3,4,5,6)

    val rdd1 = spark.parallelize(list1)

    val rdd2 = spark.parallelize(list2)

    rdd1.union(rdd2).foreach(println)

  }

}

8.join

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list1 = List((1, "东方不败"), (2, "令狐冲"), (3, "林平之"))

    val list2 = List((1, 99), (2, 98), (3, 97))

    val rdd1 = spark.parallelize(list1)

    val rdd2 = spark.parallelize(list2)

    val rdd3 = rdd1.join(rdd2)

    rdd3.foreach(tuple => {

      val id = tuple._1

      val new_tuple = tuple._2

      val name = new_tuple._1

      val score = new_tuple._2

      println("学号：" + id + " 姓名：" + name + " 成绩:" + score)

    })

  }

}

9.groupbyKey

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(("武当", "张三丰"), ("峨眉", "灭绝师太"), ("武当", "宋青书"), ("峨眉", "周芷若"))

    val rdd1 = spark.parallelize(list)

    val rdd2 = rdd1.groupByKey()

    rdd2.foreach(t => {

      val menpai = t._1

      val iterator = t._2.iterator

      var people = ""

      while (iterator.hasNext) people = people + iterator.next + " "

      println("门派:" + menpai + "人员:" + people)

    })

  }

}

10.cartesian

笛卡尔积

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list1 = List("A", "B")

    val list2 = List(1, 2, 3)

    val list1RDD = spark.parallelize(list1)

    val list2RDD = spark.parallelize(list2)

    list1RDD.cartesian(list2RDD).foreach(t => println(t._1 + "->" + t._2))

  }

}

11.filter

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(1,2,3,4,5,6,7,8,9,10)

    val listRDD = spark.parallelize(list)

    listRDD.filter(num => num % 2 ==0).foreach(print(_))

  }

}

12.distinct

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(1,1,2,2,3,3,4,5)

    val rdd = spark.parallelize(list)

    rdd.distinct().foreach(println)

  }

}

13.intersection

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list1 = List(1,2,3,4)

    val list2 = List(3,4,5,6)

    val list1RDD = spark.parallelize(list1)

    val list2RDD = spark.parallelize(list2)

    list1RDD.intersection(list2RDD).foreach(println(_))

  }

}

14.coalesce

分区有多-->少

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(1,2,3,4,5)

    spark.parallelize(list,3).coalesce(1).foreach(println(_))

  }

}

15.repartition

进行重分区

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(1,2,3,4)

    val listRDD = spark.parallelize(list,1)

    listRDD.repartition(2).foreach(println(_))

  }

}

16.repartitionAndSortWithinPartitions

在给定的partitioner内部进行排序，性能比repartition要高。

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List(1, 4, 55, 66, 33, 48, 23)

    val listRDD = spark.parallelize(list, 1)

    listRDD.map(num => (num, num))

      .repartitionAndSortWithinPartitions(new HashPartitioner(2))

      .mapPartitionsWithIndex((index, iterator) => {

        val listBuffer: ListBuffer[String] = new ListBuffer

        while (iterator.hasNext) {

          listBuffer.append(index + "_" + iterator.next())

        }

        listBuffer.iterator

      }, false)

      .foreach(println(_))

  }

}

17.cogroup

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list1 = List((1, "www"), (2, "bbs"))

    val list2 = List((1, "cnblog"), (2, "cnblog"), (3, "very"))

    val list3 = List((1, "com"), (2, "com"), (3, "good"))

    val list1RDD = spark.parallelize(list1)

    val list2RDD = spark.parallelize(list2)

    val list3RDD = spark.parallelize(list3)

    list1RDD.cogroup(list2RDD,list3RDD).foreach(tuple =>

      println(tuple._1 + " " + tuple._2._1 + " " + tuple._2._2 + " " + tuple._2._3))

  }

}

18.sortByKey

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List((99, "张三丰"), (96, "东方不败"), (66, "林平之"), (98, "聂风"))

    spark.parallelize(list).sortByKey(false).foreach(tuple => println(tuple._2 + "->" + tuple._1))

  }

}

19.aggregateByKey

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

import org.apache.spark.sql.SparkSession

import scala.collection.mutable.ListBuffer

object Demo {

  val conf = new SparkConf().setAppName("Demo").setMaster("local");

  //  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()

  val spark = new SparkContext(conf)

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

    val list = List("you,jump", "i,jump")

    spark.parallelize(list)

      .flatMap(_.split(","))

      .map((_, 1))

      .aggregateByKey(0)(_ + _, _ + _)

      .foreach(tuple => println(tuple._1 + "->" + tuple._2))

  }

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

import scala.collection.mutable.ListBuffer

object Demo {
  val conf = new SparkConf().setAppName("Demo").setMaster("local");
//  val spark = SparkSession.builder().config(conf).enableHiveSupport().getOrCreate()
val spark = new SparkContext(conf)

  def main(args: Array[String]): Unit = {
    val list = List(("武当", "张三丰"), ("峨眉", "灭绝师太"), ("武当", "宋青书"), ("峨眉", "周芷若"))
    val rdd1 = spark.parallelize(list)
    val rdd2 = rdd1.groupByKey()
    rdd2.foreach(t => {
      val menpai = t._1
      val iterator = t._2.iterator
      var people = ""
while (iterator.hasNext) people = people + iterator.next + " "
println("门派:" + menpai + "人员:" + people)
    })
  }
}

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