Structural APIs

Armed with the knowledge of how to create a graph and the knowledge of how to navigate the APIs, let's focus on the structural APIs. The code is available in graph-03.scala, graph-04.scala, and graph-05.scala files:

You can get the number of edges and vertices by numEdges and numVertices.

graph.numEdges 
graph.numVertices 
// 
val vertices = graph.vertices 
vertices.collect.foreach(println) 
// 
val edges = graph.edges 
edges.collect.foreach(println) 
// 
val triplets = graph.triplets 
triplets.take(3) 
triplets.map(t=>t.toString).collect().foreach(println) 

The triplets are interesting. They actually encompass an edge and two vertices that the edge connects to and all the user-defined objects in one neat object. They are very useful when we want to write algorithms:

Let's look at the code. It is not that complex:

val inDeg = graph.inDegrees // Followers 
inDeg.collect() 
val outDeg = graph.outDegrees...