Spark常用的算子总结（4）—— reduceByKey

 

按Key进行分组，使用给定的func函数聚合value值,

val arr = List(("A",3),("A",2),("B",1),("B",3))
val rdd = sc.parallelize(arr)
val reduceByKeyRDD = rdd.reduceByKey(_ +_)
reduceByKeyRDD.foreach(println)
sc.stop

# (A,5)
# (A,4)