[学习笔记] reduceByKey(_+_)是reduceByKey((x,y) => x+y)的一个 简洁的形式*/ val rdd08 = sc.parallelize(List((1, 1),  (1, 4),(1, 3), (3, 7), (3, 5)))    val rdd08_1 = rdd08.reduceByKey((x, y) => x + y)    println("reduceByKey 用法 " + rdd08_1.collect().mkSt…

[学习笔记] /*reduceByKey(function)reduceByKey就是对元素为KV对的RDD中Key相同的元素的Value进行function的reduce操作(如前所述),因此,Key相同的多个元素的值被reduce为一个值,然后与原RDD中的Key组成一个新的KV对. reduceByKey(_+_)是reduceByKey((x,y) => x+y)的一个 简洁的形式*/ val rdd08 = sc.parallelize(List((1, 1),  (1, 4),(1,…

[学习笔记] reduce将RDD中元素前两个传给输入函数,产生一个新的return值,将新产生的return值与RDD中下一个元素(即第三个元素)组成两个元素,再被传给输入函数,这样递归运作,直到最后只有一个值为止.*/    val rdd07 = sc.parallelize(1 to 10)    val sum = rdd07.reduce((x, y) => x + y)    println("sum is " + sum) 文章转载自原文:https://blog…

1.reduceByKey(func) 功能: 使用 func 函数合并具有相同键的值. 示例: val list = List("hadoop","spark","hive","spark") val rdd = sc.parallelize(list) val pairRdd = rdd.map((_,1)) pairRdd.reduceByKey(_+_).collect.foreach(println) 上例中,我们先…

distinct/groupByKey/reduceByKey: distinct: import org.apache.spark.SparkContext import org.apache.spark.rdd.RDD import org.apache.spark.sql.SparkSession object TransformationsDemo { def main(args: Array[String]): Unit = { val sparkSession = SparkSess…

避免使用GroupByKey 我们看一下两种计算word counts 的方法,一个使用reduceByKey,另一个使用 groupByKey: val words = Array("one", "two", "two", "three", "three", "three") val wordPairsRDD = sc.parallelize(words).map(word =>…

函数代码: class MySparkJob{ def entry(spark:SparkSession):Unit={ def getInnerRsrp(outer_rsrp: Double, wear_loss: Double, path_loss: Double): Double = { val innerRsrp: Double = outer_rsrp - wear_loss - (XX) * path_loss innerRsrp } spark.udf.register("getX…

import org.apache.spark._import SparkContext._import java.util.{Calendar,Properties,Date,Locale}import java.text.SimpleDateFormat import java.math.BigDecimal;import java.math.RoundingMode;import java.text.DecimalFormat;import java.text.NumberFormat;i…

1.利用scala语言开发spark的worcount程序(本地运行) package com.zy.spark import org.apache.spark.rdd.RDD import org.apache.spark.{SparkConf, SparkContext} //todo:利用scala语言来实现spark的wordcount程序 object WordCount { def main(args: Array[String]): Unit = { //1.创建SparkConf…

统计效果: 代码部分: import org.apache.spark.sql.hive.HiveContext import org.apache.spark.{Logging, SparkConf, SparkContext} import org.apache.spark.sql.{DataFrame, Row, SaveMode, _} import com.alibaba.fastjson.{JSON, JSONObject} import org.apache.hadoop.conf…