SparkRDD算子--mapValues算子_spark mapvalues

语法

val newRdd = oldRdd. mapValues(func)

源码

def mapValues[U](f : scala.Function1[V, U]) : org.apache.spark.rdd.RDD[scala.Tuple2[K, U]] = { /* compiled code */ }
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作用

针对于(K,V)形式的类型只对V进行操作

例子

package com.day1

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

object oper {
    def main(args: Array[String]): Unit = {
        val config:SparkConf = new SparkConf().setMaster("local[*]").setAppName("wordCount")

        // 创建上下文对象
        val sc = new SparkContext(config)

        // mapValues算子
        val arrayRdd = sc.makeRDD(Array((4,"刘六"),(2,"李四"),(3,"王五"),(1,"张三")))

        val mapRdd = arrayRdd.mapValues(_+"?")
        mapRdd.collect().foreach(println)
    }
}


输入
(4,"刘六") (2,"李四") (3,"王五") (1,"张三")
输出
(4,"刘六?") 
(2,"李四?") 
(3,"王五?") 
(1,"张三?")
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示意图

无