Hands-On Big Data Analytics with PySpark

The out-degree

The out-degree explains how many vertices are going out. This time, we'll be calculating the sources of our edges, relationships, and not destinations, like we did in the in-degree method.

To get the out-degree, we will use the following code:

val degrees = graph.outDegrees.collect().toList

The outDegrees method contains both RDD and VertexRDD, which we have collected to a list using the collect and toList methods.

Here, VertexId 1L should have two outbound vertices because there is a relationship between 1L, 2L and 1L, 3L:

  test("should calculate out-degree of vertices") {    //given    val users: RDD[(VertexId, (String))] =      spark.parallelize(Array(        (1L, "a"),        (2L, "b"),        (3L, "c"),        (4L, "d")      ))    val relationships = spark.parallelize(Array( ...