Path Traversal

Fri, 05 Aug 2022 06:29:09 GMT — Properties

Tags

Gremlin Terminology

Definitions

• Adjacent Vertex: Vertices are adjacent to another vertex if there is an edge connecting them. B, C and D are all adjacent to A. A is the only vertex adjacent to either B, C or D.
• Incident Vertex or Edge: A vertex and edge are considered incident if they are connected to each other. A is incident to E, F and G. B is only incident to E. The edge E is both incident to A and B.

Methods Applied to Vertices

• Vertices
  • out(label): Outgoing adjacent vertices. If applied to A, then B and D.
  • in(label): Incoming adjacent vertices. If applied to A, then C.
  • both(label): Outgoing and incoming adjacent vertices. If applied to A, then B, C and D.
• Edges
  • outE(label): Outgoing incident edges. If applied to A, then E and G.
  • inE(label): Incoming incident edges. If applied to A, then F.
  • bothE(label): Outgoing and incoming incident edges. If applied to A, then E, F and G.

Note that the steps can optionally take the name of one or more edge labels as a parameter. If omitted, all relevant edges will be traversed.

Methods Applied to Edges

• outV(): Outgoing vertex. If applied to E, then A.
• inV(): Incoming vertex. If applied to E, then B.
• bothV(): Both vertices. If applied to E, then A and B.
• otherV(): The vertex that was not the vertex we came from. So, if we came from A, then B and vice versa.

The above set of methods are applied to edges to return vertices.

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Notes

gremlin> g.V().has('name', 'hercules')
==> v[8360]
gremlin> g.V().has('name', 'sea')
==> v[4264]
gremlin> g.V(8360).repeat(out().simplePath()).until(hasId(4264))
    .path().limit(1)
==> path[v[8360], v[4328], v[4192], v[4264]]

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