Nodes collapse
|
returns the list of nodes merged into a VirtualNode |
Config:
On apoc.nodes.collapse
with config properties you can choose from 3 different behavior:
-
"properties": "overwrite" : if there is the same property in more node, in the new one will have the last relationship’s/node’s property value
-
"properties": "discard" : if there is the same property in more node, the new one will have the first relationship’s/node’s property value
-
"properties": "combine" : if there is the same property in more node, the new one a value’s array with all relationship’s/node’s values
If properties parameter isn’t set relationships properties are discard
.
-
"mergeRelsVirtual: true/false" : give the possibility to merge relationships with same type and direction. (DEFAULT
true
) -
"selfRel: true/false" : give the possibility to create the self relationship. (DEFAULT
false
) -
"countMerge: true/false" : give the possibility count all the Nodes/Relationships merged. (DEFAULT
true
) -
"collapsedLabel: true/false" : give the possibility to add the label
:Collapsed
to the virtualNode. (DEFAULTfalse
)
Nodes collapse example
With this dataset we have:
If we want to collapse the people living in the city to a single node, we pass them to the procedure.
MATCH (p:Person)-[:LIVES_IN]->(c:City)
WITH c, collect(p) as subgraph
CALL apoc.nodes.collapse(subgraph,{properties:'combine'}) yield from, rel, to
return from, rel, to
And get this result:
With this dataset we have:
If we also want to collapse them onto the city itself, we add the city node first to the collection.
MATCH (p:Person)-[:LIVES_IN]->(c:City)
WITH c, c + collect(p) as subgraph
CALL apoc.nodes.collapse(subgraph) yield from, rel, to
return from, rel, to
And get this result: