List comprehensions

[ilyalasy]

Hey, are list comprehensions supported in AGE? Using syntax from Neo4j doesnt seem to work, simple example:

SELECT * FROM cypher('g1', $$
MATCH (v)
RETURN [x in v.array_field]
$$) as (a agtype);

[Halkrine]

You mean that this query(array_field) is working or not with AGE?

I tried that query. Once it works as 'query' (return as jsonb from Pgadmin).

But I'm not sure this result is correct(Because it returns null).

Someone who knows this issue?

[ilyalasy]

You mean that this query(array_field) is working or not with AGE?

I tried that query. Once it works as 'query' (return as jsonb from Pgadmin).

But I'm not sure this result is correct(Because it returns null).

Someone who knows this issue?

array_field is some random array which is an attribute of a graph vertex. i'm trying it with AGE and receiving following error:

ERROR:  variable `x` does not exist
LINE 3: RETURN [x in v.array_field]

[Halkrine]

replace x -> v and try it.

[ilyalasy]

replace x -> v and try it.

no, it should be another variable: it should iterate through the array like in any list comprehension

[Halkrine]

Understood.

Maybe, that function is not supported yet now..

[JoshInnis]

Hi, List Comprehensions are not currently supported

[jasperblues]

Its a useful feature. Not sure if it will be the case on AGE but with Neo4j they can especially help with performance.

[jrgemignani]

List comp. was "nearly" completed until it was found to have serious issues for any nested cases. It will be revisited soon.