Apache Spark - Scala - HashMap (k, HashMap[String, Double](v1, v2,..)) to ((k,v1),(k,v2),…)

问题

I got:

val vector: RDD[(String, HashMap[String,Double])] = [("a", {("x",1.0),("y", 2.0),...}]

I want to get:

RDD[String,(String,Double)] = [("a",("x",1.0)), ("a", ("y", 2.0)), ...]

How can it be done with FlatMap? Better solutions are welcome!

回答1:

Try:

vector.flatMapValues(_.toSeq)

来源：https://stackoverflow.com/questions/38507249/apache-spark-scala-hashmap-k-hashmapstring-doublev1-v2-to-k-v1