apoc.map.groupBy
FunctionDeprecated in Cypher 25

This function is deprecated. Use Cypher’s map comprehension instead.

Details
Syntax	`apoc.map.groupBy(values, key)`
Description	Creates a `MAP` of the `LIST<ANY>` keyed by the given property, with single values.
Arguments	Name	Type	Description
	`values`	`LIST<ANY>`	A list of map values to be grouped.
	`key`	`STRING`	The key to group the map values by.
Returns	`MAP`

Usage examples

The following creates a map keyed by club, with a single value

apoc.map.groupBy

WITH [
	{name: "Cristiano Ronaldo", club: "Juventus"},
    {name: "Lionel Messi", club: "Barcelona"},
    {name: "Aaron Ramsey", club: "Juventus"},
    {name: "Luiz Suarez", club: "Barcelona"}
] AS listOfMaps, "club" AS group
RETURN apoc.map.groupBy(listOfMaps, groups) AS output;

Cypher’s Map Comprehension

WITH [
	{name: "Cristiano Ronaldo", club: "Juventus"},
    {name: "Lionel Messi", club: "Barcelona"},
    {name: "Aaron Ramsey", club: "Juventus"},
    {name: "Luiz Suarez", club: "Barcelona"}
] AS listOfMaps, "club" AS group
RETURN { map IN listOfMaps | map[group]: map } AS output;

Results
output
{ "Juventus": { "name": "Aaron Ramsey", "club": "Juventus" }, "Barcelona": { "name": "Luiz Suarez", "club": "Barcelona" } }