CODEWITHSUNDEEP
javaneo4jgraph-traversal
user2190709
user2190709

Reputation: 1

How to replace node ids with their respective properties?

I am using Neo4j for graph database, and using Java to extract the path from it. I have a path as follows:

[(3)--[KNOWS,5]-->(4)--[KNOWS,6]-->(5)--[KNOWS,9]-->(6)--[KNOWS,10]-->(7)--[KNOWS,12]-->(9)]

I want to replace the node ids in the path with their property. ex. For node id 3 with property "name=ABC", output should come like "[(ABC)--[KNOWS,5]....]" How it can be done?

Upvotes: 0

Views: 99

Answers (2)

Michael Hunger
Michael Hunger

Reputation: 41676

For Cypher you can use extract:

  START n=node:index(key="value")
  MATCH path=n-[:KNOWS*..5]-m
  RETURN extract(x in nodes(path) : x.name)

if you want to keep the relationships, you can do:

  RETURN extract(x in path : coalesce(x.name?,ID(x)+":"+type(x)))

see: http://console.neo4j.org/r/zvmyz

Upvotes: 1

Stefan Armbruster
Stefan Armbruster

Reputation: 39915

I assume the output we've shown is Path.toString(). There is no direct way to configure a different way of output. However you can easily iterate over the path and create your own string representation of a Path:

String myCustomPathToString(Path path) {
    StringBuilder sb = new StringBuilder();
    Node lastNode = null;
    for (PropertyContainer propertyContainer: path) {
       if (propertyContainer instanceof Node) {
          lastNode = (Node)propertyContainer
          Object default = lastNode.getId(); // as fallback
          sb.append("(").append(propertyContainer.getProperty("name", default).append(")");
       }
       if (propertyContainer instanceof Relationship) {
          Relationship rel = (Relationship)propertyContainer ;
          Object id = rel.getId();
          if (rel.getEndNode().equals(lastNode)) sb.append("<");
          sb.append("--[").append(rel.getType().name()).append(",").append(id).append("]--");
          if (rel.getStartNode().equals(lastNode)) sb.append(">");              
       }
    }
    return sb.toString();
}

DISCLAIMER: I did not test the snippet above, so it's more a guidline than a working example.

Upvotes: 2

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