title: I want to flatten org.apache.spark.rdd.RDD[(Any, scala.collection.immutable.Iterable[String])] to String in Scala
body: <p>Example </p>
  
  <p>(168,20874,List(, 33895, 2711))                                                 </p>
  
  <p>to   168,20874| , 33895, 2711</p>
  
  <p>Basically convert RDD[(Any, scala.collection.immutable.Iterable[String])] to String.</p>
  
  <p>Thanks</p>