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Paths and traversal

ecoologic edited this page Oct 12, 2012 · 2 revisions

Find paths between nodes

@neo.get_path(node1, node2, relationships, depth=4, algorithm="shortestPath") # finds the shortest path between two nodes
@neo.get_paths(node1, node2, relationships, depth=3, algorithm="allPaths")    # finds all paths between two nodes
@neo.get_shortest_weighted_path(node1, node2, relationships,   # find the shortest path between two nodes
                                weight_attr='weight', depth=2, # accounting for weight in the relationships
                                algorithm='dijkstra')          # using 'weight' as the attribute

Node traversal:

nodes = @neo.traverse(node1,                                              # the node where the traversal starts
                      "nodes",                                            # return_type "nodes", "relationships" or "paths"
                      {"order" => "breadth first",                        # "breadth first" or "depth first" traversal order
                       "uniqueness" => "node global",                     # See Uniqueness in API documentation for options.
                       "relationships" => [{"type"=> "roommates",         # A hash containg a description of the traversal
                                            "direction" => "all"},        # two relationships.
                                           {"type"=> "friends",           #
                                            "direction" => "out"}],       #
                       "prune evaluator" => {"language" => "javascript",  # A prune evaluator (when to stop traversing)
                                             "body" => "position.endNode().getProperty('age') < 21;"},
                       "return filter" => {"language" => "builtin",       # "all" or "all but start node"
                                           "name" => "all"},
                       "depth" => 4})

"depth" is a short-hand way of specifying a prune evaluator which prunes after a certain depth.

Traversal algorithms can be found in NodePath module, relationships are of the format {"type" => relationship_name, "direction" => "in"} where possible directions are in, out and all.

If not specified a depth of 1 is used and if a "prune evaluator" is specified instead of a depth, no depth limit is set.

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