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gremlinjanusgraph

Finding out which Vertex and edges were traversed

I have the following Graph

enter image description here

If I write a Query g.V('A').Out(), how can I get that the values of the Edges which were traversed and the vertex which were encounterned in the traveral ?

Solution

  • You would need to tell Gremlin to not skip the edges. g.V().out() is shorthand for g.V().outE().inV(). In this case, you can interact with the value of the edges as you've explicitly told Gremlin to traverse them. I'll demonstrate with a few examples using the "modern" toy graph:

    gremlin> g = TinkerFactory.createModern().traversal()
==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]

    To start, you might want to filter on a particular edge property and then traverse to adjacent vertices:

    gremlin> g.V().outE().has('weight',gt(0.5)).inV()
==>v[4]
==>v[5]

    You mentioned in your question that you might want to see the values of edges and the vertices you encountered. One way would be to use path():

    gremlin> g.V().outE().has('weight',gt(0.5)).inV().path()
==>[v[1],e[8][1-knows->4],v[4]]
==>[v[4],e[10][4-created->5],v[5]]

    You might also get more explicit to get specific properties from the edge:

    gremlin> g.V().outE().has('weight',gt(0.5)).inV().path().by().by('weight')
==>[v[1],1.0,v[4]]
==>[v[4],1.0,v[5]]