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gremlintinkerpop3

TinkerPop: Filter by Edge not connected with an Edge

Sample database: TinkerPop Modern

Objective: Find People who have not developed a Software.

ie. Vertex type "Person" that is not directly connected to Vertex type "Software"

Person connected to Software [Works]

g.V().hasLabel("Person").as("from")
.project("title", "node")
    .by(select("from").unfold().values("name").fold())
    .by(select("from").unfold().label().fold())

Find Person not connected to Software [Does not work]

g.V().hasLabel("Person").as("from")
.filter(both().not(hasLabel("Software")))
.project("title", "node")
    .by(select("from").unfold().values("name").fold())
    .by(select("from").unfold().label().fold())

I believe its ignoring an edge that does not satisfy the condition, but does not skip the Vertex.

Tried to do a loop but did not find an example for it.

Cypher Query equivalent (for reference only): MATCH (n:People) WHERE NOT (n)--(:Software) RETURN n

Sample database:

enter image description here

Solution

  • I believe that you just need to change your filter criteria:

    gremlin> g.V().hasLabel('person').
......1>   filter(__.not(outE('created'))).
......2>   project("title", "node").
......3>     by('name').
......4>     by(label)
==>[title:vadas,node:person]

    As you can see, you also don't need to select back to that as() step for any reason - you already have that vertex as the current traverser in project().