Get all paths in a graph from a node, but only ones which terminate

Question

I have written the following query which returns all paths possible from the specified node.

g.V(<some_id>).repeat(bothE().bothV().simplePath()).emit().dedup().path()

If we had a simple graph of 3 nodes in this structure:

A -- edge_1 -> B -- edge_2 -> C

this query would return two paths:

A, edge_1, B
A, edge_1, B, edge_2, C

However, I only want to return all paths that terminate (i.e. there is no further nodes to traverse), which in this example would only return

A, edge_1, B, edge_2, C

Is this possible?

score 1 · Answer 1 · answered Sep 08 '20 at 12:09

1

You can try to do the repeat without the emit step and use until to stop at the end of the path.

g.V().hasLabel('A').repeat(bothE().bothV().
    simplePath()).
  until(bothE().simplePath().
    count().is(eq(0))).dedup().path()

answered Sep 08 '20 at 12:09

noam621

There are actually some instances where I am not getting the results I want, such as when there are loops in the graph. Here is one such example: https://gremlify.com/ccocxr1uau. Also to add to my original post, I want all nodes and all edges to be returned in the paths, but no one path returned should be a "sub-path" of another. Any ideas how to correct this? – KOB Sep 09 '20 at 10:04
@KOB in this case of a circle with different edges if you change the `bothE` to `both` you will get the routes https://gremlify.com/tja7crvmg4b – noam621 Sep 09 '20 at 11:26
Ok it works, but I don't understand why the second path doesn't terminate at node 4, but instead continues to both nodes 3 and 2. Can you explian? Ideally I would want the second path just to have 1, D, 4 (i.e. returning the edge, D, that the first path didn't include. The first path already incldues 2, B, 3, C, so I don't need these returned in the second. – KOB Sep 09 '20 at 12:42
@KOB Because the two are distinguished by one edge from 1 to another, so no one is a subpath of the other, you need to consider if you really need to travel both directions and not going only on the out edges. – noam621 Sep 09 '20 at 12:56
1

Ok I see. I don't need to travel in both directions. In short, all I need is the minimal amount of minimal length paths that collectively traverse all nodes and edges in the graph, if that makes sense? I am open to any other suggestions on queries that would achieve this – KOB Sep 09 '20 at 13:46

1 Answers1