apoc.map.mergeList
Function

Details

Syntax

apoc.map.mergeList(maps)

Description

Merges all MAP values in the given LIST<MAP<STRING, ANY>> into one MAP.

Arguments

Name

Type

Description

maps

LIST<MAP>

A list of maps to merge.

Returns

MAP

Usage examples

The following merges multiple maps:

apoc.map.mergeList
WITH [
    {name: "Cristiano Ronaldo"},
    {dob: date("1985-02-05")},
    {country: "Portugal"}
] AS maps
RETURN apoc.map.mergeList(maps) AS output
Cypher’s Map Comprehension
WITH [
    {name: "Cristiano Ronaldo"},
    {dob: date("1985-02-05")},
    {country: "Portugal"}
] AS maps
WITH coll.flatten(collect([k IN keys(maps) | [k, maps[k]]]), 1) AS allEntries
RETURN { kv IN allEntries | kv[0] : kv[1]} AS output
Results
output 
{
  "name": "Cristiano Ronaldo",
  "country": "Portugal",
  "dob": "1985-02-05"
}

apoc.map.mergeList iterates over the list sequentially as it merges. This means that if the same key is used for different values, the last unique key-value pair in the list will be in the resulting map.

apoc.map.mergeList
WITH [
    {name: "Cristiano Ronaldo"},
    {dob: date("1985-02-05")},
    {profession: "Athlete"},
    {profession: "Football player"}
] AS maps
RETURN apoc.map.mergeList(maps) AS output
Cypher’s Map Comprehension
WITH [
    {name: "Cristiano Ronaldo"},
    {dob: date("1985-02-05")},
    {profession: "Athlete"},
    {profession: "Football player"}
] AS maps
WITH coll.flatten(collect([k IN keys(maps) | [k, maps[k]]]), 1) AS allEntries
RETURN { kv IN allEntries | kv[0]: kv[1]} AS output
Results
output 
{
  "name": "Cristiano Ronaldo",
  "profession": "Football player",
  "dob": "1985-02-05"
}