apoc.map.submap

Details
Syntax	`apoc.map.submap(map, keys [, values, fail ])`
Description	Returns a sub-map for the given keys. If one of the keys does not exist, or lacks a default value, this function will throw an exception.
Arguments	Name	Type	Description
	`map`	`MAP`	The map to extract a submap from.
	`keys`	`LIST<STRING>`	The list of keys to extract into a submap.
	`values`	`LIST<ANY>`	The default values of the given keys. The default is: `[]`.
	`fail`	`BOOLEAN`	If a key is not present and no default is provided, it will either throw an exception if true, or return a null value. The default is: `true`.
Returns	`MAP`

Usage Examples

The following returns a MAP containing only the key a:

RETURN apoc.map.submap({a:1,b:1},['a']) AS output;

Results
Output
{a: 1}

The following throw an exception because the map doesn’t contain the key c:

RETURN apoc.map.submap({a:1,b:1},['c']) AS output;

Results
Failed to invoke function `apoc.map.submap`: Caused by: java.lang.IllegalArgumentException: Key c is not of one of the existing keys [a, b]

The following returns a MAP containing a default value of 42 for the missing key c:

RETURN apoc.map.submap({a:1,b:1},['c'], [42]) AS output;

Results
Output
{c: 42}

The following returns a MAP containing a null value for the missing key c:

RETURN apoc.map.submap({a:1,b:1},['c'], null, false) AS output;

Results
Output
{c: NULL}