wordCount3 (aggregateByKey)
2019-07-31 本文已影响0人
yayooo
初始值为0,分区内相加,分区间相加。
package com.atguigu
import org.apache.spark.rdd.RDD
import org.apache.spark.{HashPartitioner, Partitioner, SparkConf, SparkContext}
object Trans {
def main(args: Array[String]): Unit = {
val conf: SparkConf = new SparkConf().setMaster("local[*]").setAppName("Spark01_Partition")
//构建spark上下文对象
val sc = new SparkContext(conf)
val rdd: RDD[(String, Int)] = sc.makeRDD(List(("a",1),("b",2),("b",3),("a",3),("b",4),("a",5)),2)
val rdd2: RDD[(String, Int)] = rdd.aggregateByKey(0)((x,y) => {x+y},(x,y) => {x+y})
rdd2.collect().foreach(println)
sc.stop()
}
}
(b,9)
(a,9)