Graphx Scala:在具有属性继承的顶点上应用过滤器 [英] Graphx Scala: Applying filter on Vertex with Property Inheritance

问题描述

我的顶点具有不同的属性.现在，我想过滤掉具有特定属性值的对象.这是我的代码的样子:

I've vertices with different properties. Now I want to filter out those with a specific property value. Here's how my code looks like:

// Different property classes for different vertex
class VertexProperty()
case class Property1(val name: String, val servings: Int) extends VertexProperty
case class Property2(val description: String) extends VertexProperty
case class Property3(val name: String, val quantity: Double, val measurementUnit: String) extends VertexProperty

val vertexArray = Array(
    (1L, Property1("propertyName",8)),
    (2L, Property2("property description")),
    (3L, Property3("", 1,"lb."))
    )

 val edgeArray = Array(
     Edge(1L, 2L, "step1"),
     Edge(1L, 3L, "step2")
     )

 val vertexRDD: RDD[(Long, VertexProperty)] = sc.parallelize(vertexArray) 
 val edgeRDD: RDD[Edge[String]] = sc.parallelize(edgeArray)
 val graph: Graph[VertexProperty, String] = Graph(vertexRDD, edgeRDD)

现在我要过滤顶点，该顶点的属性为 Property2 ，并且其描述不为空，我尝试通过以下方式进行操作:

Now I want to filter vertices, which property is Property2 and whose description is not empty, I tried in these ways:

1. 没有给出预期的结果

1. It's not giving expected result

graph.vertices.filter { case (id, (descrition)) => descrition !="" }.foreach{
  case (id, (descrition)) => println(s"$descrition")
}

此代码不起作用

This code is not working

graph.vertices.filter { case (id, Property2(descrition)) => descrition !=""}.foreach{
  case (id, (descrition)) => println(s"$descrition")
}

推荐答案

您尝试过的代码很接近，但并不完全正确.您需要在 filter 中使用两种情况；一种用于 Property2 ，另一种用于所有其他情况.

The code you have tried is close but not exactly correct. You need two cases in the filter; one for the Property2 and one for all other cases.

val vertices = graph.vertices.filter{
  case (id, vp: Property2) => vp.description != ""
  case _ => false
}

这将为您提供一个 VertexRDD [VertexProperty] ，其中包含满足要求的所有顶点.

This will give you a VertexRDD[VertexProperty] with all the vertices that fulfill the requirements.

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