Compare data in two RDD in spark

Question

I am able to print data in two RDD with the below code.

usersRDD.foreach(println)
empRDD.foreach(println)

I need to compare data in two RDDs. H

Answer 1

You need to key the data in each RDD so that there is something to join records on. Have a look at groupBy for example. Then you join the resulting RDDs. For each key, you get the matching values in both. If you are interested in finding the unmatched keys, use leftOuterJoin, like this:

// Returns the entries in userRDD that have no corresponding key in empRDD.
def nonEmp(userRDD: RDD[(String, String)], empRDD: RDD[(String, String)]) = {
  userRDD.leftOuterJoin(empRDD).collect {
    case (name, (age, None)) => name -> age
  }
}