apoc.coll.flatten
FunctionDeprecated in 25

This function is deprecated. Use Cypher’s coll.flatten() function instead.

Details
Syntax	`apoc.coll.flatten(coll [, recursive ])`
Description	Flattens the given `LIST<ANY>` (to flatten nested `LIST<ANY>` values, set recursive to true).
Arguments	Name	Type	Description
	`coll`	`LIST<ANY>`	The list to flatten.
	`recursive`	`BOOLEAN`	Whether nested list items should also be flattened. The default is: `false`.
Returns	`LIST<ANY>`

Usage examples

The following flattens a collection of collections using both APOC and Cypher:

apoc.coll.flatten

RETURN apoc.coll.flatten([1,2,3,[4,5,6]]) AS output;

Cypher’s coll.flatten

RETURN coll.flatten([1,2,3,[4,5,6]]) AS output;

Results
Output
[1, 2, 3, 4, 5, 6]

The following flattens a collection of collections by a depth of one using both APOC and Cypher:

apoc.coll.flatten

RETURN apoc.coll.flatten([1,2,3,[[4,[5,6]]]]) AS output;

Using Cypher’s coll.flatten

RETURN coll.flatten([1,2,3,[[4,[5,6]]]]) AS output;

Results
Output
[1, 2, 3, [4, [5, 6]]]

The following flattens a collection of collections recursively until all levels are flattened using both APOC and Cypher:

apoc.coll.flatten

RETURN apoc.coll.flatten([1,2,3,[[4,[5,6]]]], true) AS output;

Using Cypher’s coll.flatten

RETURN coll.flatten([1,2,3,[[4,[5,6]]]], 1000) AS output;

Results
Output
[1, 2, 3, 4, 5, 6]