Path Functions

Example Graph

GQL
INSERT (p1:Paper {_id:'P1', title:'Efficient Graph Search', score:6, author:'Alex'}),
       (p2:Paper {_id:'P2', title:'Optimizing Queries', score:9, author:'Alex'}),
       (p3:Paper {_id:'P3', title:'Path Patterns', score:7, author:'Zack'}),
       (p1)-[:Cites {weight:2}]->(p2),
       (p2)-[:Cites {weight:1}]->(p3)

path_length()

Returns the number of edges in a path.

GQL
MATCH p = ()->{1,3}()
RETURN p, path_length(p) AS length

Result:

elements()

Returns a list containing the nodes and edges that make up a path, interleaved in order.

GQL
MATCH p = ()->()
LET items = elements(p)
FOR item IN items WITH ORDINALITY index
FILTER index %2 = 1
RETURN item

Result:

JSON
[
  {"id": "P2", "labels": ["Paper"], "properties": {"title": "Optimizing Queries", "author": "Alex", "score": 9}},
  {"id": "P3", "labels": ["Paper"], "properties": {"title": "Path Patterns", "author": "Zack", "score": 7}},
  {"id": "P1", "labels": ["Paper"], "properties": {"title": "Efficient Graph Search", "author": "Alex", "score": 6}},
  {"id": "P2", "labels": ["Paper"], "properties": {"title": "Optimizing Queries", "author": "Alex", "score": 9}}
]

pnodes()

Returns the nodes of a path as a list. nodes() is a synonym.

GQL
MATCH p = ({_id: "P1"})->()
RETURN pnodes(p)

Result:

JSON
[
  {
    "id": "P1",
    "labels": ["Paper"],
    "properties": {"score": 6, "author": "Alex", "title": "Efficient Graph Search"}
  },
  {
    "id": "P2",
    "labels": ["Paper"],
    "properties": {"title": "Optimizing Queries", "score": 9, "author": "Alex"}
  }
]

pedges()

Returns the edges of a path as a list. relationships() is a synonym.

GQL
MATCH p = ({_id: "P1"})->()
RETURN pedges(p)

Result:

JSON
[
  {
    "id": "e:1",
    "label": "Cites",
    "fromNodeId": "P1",
    "toNodeId": "P2",
    "properties": {"weight": 2}
  }
]

pnodeIds()

Collects the _id values of nodes in a path into a list.

GQL
MATCH p = ({_id: "P1"})-[]->{1,2}()
RETURN pnodeIds(p)

Result:

pedgeUuids()

Collects the _id values of edges in a path into a list.

GQL
MATCH p = ({_id: "P1"})-[]->{1,2}()
RETURN pedgeUuids(p)

Result: