masavini
January 12, 2023, 10:38am
1
Hi everybody!
I have a graph with a few thousand nodes which form unrelated clusters. I'd like to get a list of lists with the nodes with a certain label forming each cluster, regardless of the relation type linking them.
Let's consider this simple example:
CREATE
(:Person {name: "Andrea"})-[:LOVES]->(:Person {name: "Bob"})-[:LIKES]->(:Food {name: "pizza"}),
(n:Person {name: "Mike"})<-[:KNOWS]-(:Person {name: "Paul"})-[:KNOWS]->(:Person {name: "Jen"})<-[:LOVES]-(n)
If I'd like to know which persons are somehow related, then I would get:
[
["Andrea", "Bob"],
["Mike", "Paul", "Jen"]
]
Could please help me building such a query? Thanks!
masavini
January 12, 2023, 11:05pm
2
what can i say? OUTSTANDING job, guys. never seen such a good support before, congratulations.
masavini
January 12, 2023, 11:39am
3
Thank you very much, that is exactly what I was looking for.
So I first projected a new graph:
CALL gds.graph.project(
'myGraph',
'Person',
'*'
)
Then I retrieved information about each cluster (aka component) in myGraph:
CALL gds.wcc.stream('myGraph')
YIELD nodeId, componentId
RETURN gds.util.asNode(nodeId).name AS name, componentId
ORDER BY componentId, name
╒════════╤═════════════╕
│"name" │"componentId"│
╞════════╪═════════════╡
│"Andrea"│0 │
├────────┼─────────────┤
│"Bob" │0 │
├────────┼─────────────┤
│"Jen" │2 │
├────────┼─────────────┤
│"Mike" │2 │
├────────┼─────────────┤
│"Paul" │2 │
└────────┴─────────────┘
Could you suggest how to group names inside a list of lists?
This groups the names by componentId. Do you want further grouping?
CALL gds.wcc.stream('myGraph')
YIELD nodeId, componentId
RETURN collect(gds.util.asNode(nodeId).name) AS names, componentId
ORDER BY componentId
Can you give an example about 'list of lists'. What kind of data is this?
masavini
January 12, 2023, 1:37pm
7
in the example above, something like this:
[
["Andrea", "Bob"],
["Mike", "Paul", "Jen"]
]
a list of components where each component is represented by a list of node names.
In neo4j there is no explicit grouping logic. Group by works with aggregate functions so I will use 'count'. I suppose something similar to this would work for you.
WITH [
["Andrea", "Bob", "Andrea"],
["Mike", "Paul", "Jen","Bob"]
] as myList UNWIND myList as subList UNWIND subList as name return name, count(name)
returns
"Andrea" 2
"Bob" 2
"Mike" 1
"Paul" 1
"Jen" 1
