Predicates are boolean functions that return true or false for a given set of input. They are most commonly used to filter out subgraphs in the WHERE part of a query.

Tests the predicate closure to see if all items in the iterable match.

Syntax: ALL(iterable, [symbol ⇒] predicate-closure) Arguments: iterable: An array property, or an iterable symbol, or an iterable function. symbol: The closure will have a symbol introduced in it’s context. Here you decide which symbol to use. If you leave the symbol out, the default symbol _ (underscore) will be used. predicate-closure: A predicate that is tested against all items in iterable

Graph

Query

start a=(3), b=(1) match p=a-[^1..3]->b where all(nodes(p), x => x.age > 30) return p

All nodes in the path.

Result

 +-------------------------------------------------------------------+
 | p                                                                 |
 +-------------------------------------------------------------------+
 | Path(Node[3], Relationship[1], Node[5], Relationship[3], Node[1]) |
 +-------------------------------------------------------------------+
 1 rows, 3 ms

Tests the predicate closure to see if at least one item in the iterable match.

Syntax: ANY(iterable, [symbol ⇒] predicate-closure) Arguments: iterable: An array property, or an iterable symbol, or an iterable function. symbol: The closure will have a symbol introduced in it’s context. Here you decide which symbol to use. If you leave the symbol out, the default symbol _ (underscore) will be used. predicate-closure: A predicate that is tested against all items in iterable

Graph

Query

start a=(3) match p=a-[^1..3]->b where any(nodes(p), x => x.eyes = "blue") return p

All nodes in the path.

Result

 +-------------------------------------------------------------------+
 | p                                                                 |
 +-------------------------------------------------------------------+
 | Path(Node[3], Relationship[0], Node[4])                           |
 | Path(Node[3], Relationship[0], Node[4], Relationship[2], Node[1]) |
 | Path(Node[3], Relationship[0], Node[4], Relationship[4], Node[2]) |
 +-------------------------------------------------------------------+
 3 rows, 5 ms

Tests the predicate closure to see if no items in the iterable match. If even one matches, the function returns false.

Syntax: NONE(iterable, [symbol ⇒] predicate-closure) Arguments: iterable: An array property, or an iterable symbol, or an iterable function. symbol: The closure will have a symbol introduced in it’s context. Here you decide which symbol to use. If you leave the symbol out, the default symbol _ (underscore) will be used. predicate-closure: A predicate that is tested against all items in iterable

Graph

Query

start n=(3) match p=n-[^1..3]->b where NONE(nodes(p), x => x.age = 25) return p

All nodes in the path.

Result

 +-------------------------------------------------------------------+
 | p                                                                 |
 +-------------------------------------------------------------------+
 | Path(Node[3], Relationship[1], Node[5])                           |
 | Path(Node[3], Relationship[1], Node[5], Relationship[3], Node[1]) |
 +-------------------------------------------------------------------+
 2 rows, 5 ms

Returns true if the closure predicate matches exactly one of the items in the iterable.

Syntax: SINGLE(iterable, [symbol ⇒] predicate-closure) Arguments: iterable: An array property, or an iterable symbol, or an iterable function. symbol: The closure will have a symbol introduced in it’s context. Here you decide which symbol to use. If you leave the symbol out, the default symbol _ (underscore) will be used. predicate-closure: A predicate that is tested against all items in iterable

Graph

Query

start n=(3) match p=n-->b where SINGLE(nodes(p), _.eyes = "blue") return p

All nodes in the path.

Result

 +-----------------------------------------+
 | p                                       |
 +-----------------------------------------+
 | Path(Node[3], Relationship[0], Node[4]) |
 +-----------------------------------------+
 1 rows, 2 ms

Scalar functions return a single value.

To return or filter on the length of a path, use the special property LENGTH

Syntax: LENGTH( iterable ) Arguments: iterable: An iterable, value or function call

Graph

Query

start a=(3) match p=a-->b-->c return length(p)

The length of the path p.

Result

 +-----------+
 | LENGTH(p) |
 +-----------+
 | 5         |
 | 5         |
 | 5         |
 +-----------+
 3 rows, 4 ms

Returns a string representation of the relationship type.

Syntax: TYPE( relationship ) Arguments: relationship: A relationship

Graph

Query

start n=(3) match (n)-[r]->() return type(r)

The relationship type of r.

Result

 +---------+
 | TYPE(r) |
 +---------+
 | KNOWS   |
 | KNOWS   |
 +---------+
 2 rows, 1 ms

Returns the id of the relationship or node

Syntax: ID( property-container ) Arguments: property-container: A node or a relationship

Graph

Query

start a=(3, 4, 5) return ID(a)

The node id for three nodes.

Result

 +-------+
 | ID(a) |
 +-------+
 | 3     |
 | 4     |
 | 5     |
 +-------+
 3 rows, 0 ms

Iterable functions return an iterable of things - nodes in a path, and so on.

Returns all nodes in a path

Syntax: NODES( path ) Arguments: path: A path

Graph

Query

start a=(3), c=(2) match p=a-->b-->c return NODES(p)

All the nodes in the path p.

Result

 +---------------------------------+
 | NODES(p)                        |
 +---------------------------------+
 | List(Node[3], Node[4], Node[2]) |
 +---------------------------------+
 1 rows, 2 ms

Returns all relationships in a path

Syntax: RELATIONSHIPS( path ) Arguments: path: A path

Graph

Query

start a=(3), c=(2) match p=a-->b-->c return RELATIONSHIPS(p)

All the nodes in the path p.

Result

 +----------------------------------------+
 | RELATIONSHIPS(p)                       |
 +----------------------------------------+
 | List(Relationship[0], Relationship[4]) |
 +----------------------------------------+
 1 rows, 3 ms