Random values in cypher

Neo4j Graph Platform
1

Hi,
is there a chance to use MIN, MAX in Cypher like in the following example, or is it possible to save the rand()- value into a variable and use the variable in the same cypher- statement.

MATCH (:Person)-[c:Meeting]->(q:Person)
WHERE (q.att1 = 0) AND
	( rand() < MIN( 0.25, MAX( 0.01, 1 / MAX( 1,  c.distance/1000.0))))
SET q.att2 = 1

You see, I'm a beginner. Thanks for your help.

Reinhold

2

Hello:)

WITH rand() AS r
MATCH (:Person)-[c:Meeting]->(q:Person)
WHERE (q.att1 = 0)
AND (r < MIN( 0.25, MAX( 0.01, 1 / MAX( 1,  c.distance/1000.0))))
SET q.att2 = 1
3

Thank you very much!

Reinhold

4

No problem, a pleasure:)

5

Hi,
sorry for another question. I suppose, the statement above produces only one random value for each query. Is this correct? But I need a random value for each selected record. Does following query works?

MATCH (:Person)-[c:Meeting]->(q:Person)
WHERE (q.att1 = 0)
AND (rand() < MIN( 0.25, MAX( 0.01, 1 / MAX( 1, c.distance/1000.0))))
SET q.att2 = 1

I didn't know that MIN/MAX statements works in Cypher.
And sorry for my English.

Reinhold

6

Yes, you right, but if you still want to keep the rand value to use it later in the query, try this:

MATCH (:Person)-[c:Meeting]->(q:Person)
WHERE q.att1 = 0
WITH q, c.distance AS dist, rand() AS r
WHERE (r < MIN( 0.25, MAX( 0.01, 1 / MAX( 1, dist/1000.0))))
SET q.att2 = 1