scala - 我如何用这个在 GraphX 中创建一个图形

Question

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Answer 1

读取 hdfs 源代码并将数据保存在 rdd 中后，您可以尝试如下操作:

import org.apache.spark.rdd.RDD
import org.apache.spark.graphx.Edge
// Sample data
val rdd = sc.parallelize(Seq("1: 1, 2, 3", "2: 2, 3"))

val edges: RDD[Edge[Int]] = rdd.flatMap {
  row => 
    // split around ":"
    val splitted = row.split(":").map(_.trim)
    // the value to the left of ":" is the source vertex:
    val srcVertex = splitted(0).toLong
    // for the values to the right of ":", we split around "," to get the other vertices
    val otherVertices = splitted(1).split(",").map(_.trim)
    // for each vertex to the right of ":", we create an Edge object connecting them to the srcVertex:
    otherVertices.map(v => Edge(srcVertex, v.toLong, 1))
}

编辑

此外，如果您的顶点具有恒定的默认权重，您可以直接从边创建图形，因此您不需要创建 verticesRDD:

import org.apache.spark.graphx.Graph
val g = Graph.fromEdges(edges, defaultValue = 1)