Filtering a Gremlin Traversal by edge label

Question

I am trying to use Gremlin to traverse outwards from a starting node to all connected nodes within X degrees of connection. The direction of the connection does not matter, so I am using the both() function. I also want to be able to prevent the traversal from crossing edges with specific labels. Here's a sample graph.

gremlin> g.addV().property(id,1).as('1').
......1>   addV().property(id,2).as('2').
......2>   addV().property(id,3).as('3').
......3>   addV().property(id,4).as('4').
......4>   addV().property(id,5).as('5').
......5>   addV().property(id,6).as('6').
......6>   addV().property(id,7).as('7').
......7>   addE('edge1').from('1').to('2').
......8>   addE('edge2').from('1').to('3').
......9>   addE('edge2').from('2').to('4').
.....10>   addE('edge3').from('3').to('5').
.....11>   addE('edge3').from('4').to('6').
.....12>   addE('edge4').from('7').to('6').iterate()

The traversal that I have so far looks like this:

gremlin> g.V(1).
......1>   repeat(both().filter(not(inE('edge3')))).
......2>   times(4).
......3>   emit().
......4>   simplePath().
......5>   dedup()

However this is not quite what I am looking for. I want something which will actually prevent the traverser from hitting a vertex if it has to cross the specified edge. My current implementation filters vertices which have the incoming edge, but in some cases I may still want that vertex to appear in the results if the traverser crossed a different edge to get there.

Does this make sense? In short, I am trying to specifically filter on an edge rather than on a vertex's relationship to its edges.

stephen mallette stephen mallette · Accepted Answer · 2018-10-17T20:48:17

I think I followed what you were saying, couldn't you just use bothE() and filter those edges while traversing them:

gremlin> g.V(1).
......1>   repeat(bothE().not(hasLabel('edge3')).otherV()).
......2>     times(4).
......3>     emit().
......4>   simplePath().
......5>   dedup()
==>v[2]
==>v[3]
==>v[4]

Filtering a Gremlin Traversal by edge label

1 Answers