Neo4j: count the size of array

[Ebtihel Hannachi]

Hi, 

I am new in graph databases and I need your help, please!

so I have created a set of nodes, every node has as properties name and an array of integers.

I would like to know how to get all nodes have only a single integer???

I tried this query but it gave no results "MATCH (v) WITH length(v.value) as size WHERE size=1 RETURN v.name".

[Michael Hunger]

Your query looks ok, it could be shortened to:

Cypher is case sensitive so perhaps you have a misspelling somewhere?

match (v) where size(v.value) = 1 return v.name

you can check with

match (v) return v.name, size(v.value) limit 20

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[Chris Vest]

If you want this to be a fast thing to query for, you can put the array length in a separate property on the nodes, and then create an index for it. Then change your queries to be for `v.length = 1`, etc.

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Chris Vest
System Engineer, Neo Technology

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[Ebtihel Hannachi]

it worked form me with index !! i really appreciate it :)

2018-05-07 10:31 GMT+01:00 'Chris Vest' via Neo4j <ne...@googlegroups.com>:

If you want this to be a fast thing to query for, you can put the array length in a separate property on the nodes, and then create an index for it. Then change your queries to be for `v.length = 1`, etc.

--
Chris Vest
System Engineer, Neo Technology

> On 7 May 2018, at 11.10, 'Michael Hunger' via Neo4j <ne...@googlegroups.com> wrote:
>
> Your query looks ok, it could be shortened to:
>
> Cypher is case sensitive so perhaps you have a misspelling somewhere?
>
> match (v) where size(v.value) = 1 return v.name
>
> you can check with
>
> match (v) return v.name, size(v.value) limit 20
>
>
> On Sat, May 5, 2018 at 3:56 PM, Ebtihel Hannachi <hannachi...@gmail.com> wrote:
> Hi,
> I am new in graph databases and I need your help, please!
> so I have created a set of nodes, every node has as properties name and an array of integers.
> I would like to know how to get all nodes have only a single integer???
> I tried this query but it gave no results "MATCH (v) WITH length(v.value) as size WHERE size=1 RETURN v.name".
>
> --
> You received this message because you are subscribed to the Google Groups "Neo4j" group.

> To unsubscribe from this group and stop receiving emails from it, send an email to neo4j+unsubscribe@googlegroups.com.

> For more options, visit https://groups.google.com/d/optout.
>
>
> --
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[Ebtihel Hannachi]

I have another question, please!

What about if I would like to delete a specific value from an array without knowing the indices of it in the array  (example array[10,20,30) and the result will be [10,30]).

any suggestions, please? I'll be so grateful!

[Michael Hunger]

return filter(x in [10,20,30] where x <> 20)

[Ebtihel Hannachi]

it works very well :) thank you