Apache Spark GraphX: deal with relationships involving Strings as their id instead of numbers

• Example

• import org.apache.spark._ import org.apache.spark.graphx._ import org.apache.spark.rdd.RDD import scala.collection.mutable.ArrayBuffer import collection.mutable.HashMap    val vertices = ArrayBuffer[(Long, (String, String, String))]() val vertice_map = new HashMap[String,Long]()  { override def default(key:String) = 0 } val airport_data = scala.io.Source.fromFile("/resources/airports.csv") var counter = 1 for (line <- airport_data.getLines()) {     val cols = line.split(",")     if (cols(4) != "\\N" && cols(4) != "") {         vertice_map += (cols(4) -> counter)         vertices += ((counter, (cols(4), cols(1), cols(3))))         counter += 1     } } for (line <- vertices) {     println(line) } val plane_vertexRDD: RDD[(Long, (String, String, String))] = sc.parallelize(vertices)    val edges = ArrayBuffer[Edge[String]]() val route_data = scala.io.Source.fromFile("/resources/routes.csv") for (line <- route_data.getLines()) { val cols = line.split(",") if (vertice_map(cols(2)) != 0 || vertice_map(cols(4)) != 0) { edges += (Edge(vertice_map(cols(2)), vertice_map(cols(4)), cols(0))) } } for (line <- edges) { println(line) } val plane_edgeRDD: RDD[Edge[String]] = sc.parallelize(edges)    var default_plane_vertex = ("Location", "Currently", "Unknown") val plane_graph = Graph(plane_vertexRDD, plane_edgeRDD, default_plane_vertex) for (triplet <- plane_graph.triplets.collect) { print(triplet.srcAttr._1) print(" to ") print(triplet.dstAttr._1) print(" with Arline ") println(triplet.attr) }    val plane_graph_fixed = plane_graph.subgraph(vpred = (id, user_type) => user_type._1 != "Location") for (triplet <- plane_graph_fixed.triplets.collect) { print(triplet.srcAttr._1) print(" to ") print(triplet.dstAttr._1) print(" with Arline ") println(triplet.attr) }