apoc.map.get

Details
Syntax	`apoc.map.get(map, key [, value, fail ])`
Description	Returns a value for the given key. If the given key 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 value from.
	`key`	`STRING`	The key to extract.
	`value`	`ANY`	The default value of the given key. The default is: `null`.
	`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	`ANY`

Usage Examples

The following throws an exception when attempting to look up missing key missingKey with no default value:

WITH {name:"Cristiano Ronaldo",country:"Portugal",dob:date("1985-02-05")} AS map
RETURN apoc.map.get(map, "missingKey") AS output;

Results
Output
Neo.ClientError.Procedure.ProcedureCallFailed: Failed to invoke function `apoc.map.get`: Caused by: java.lang.IllegalArgumentException: Key missingKey is not of one of the existing keys [country, dob, name]

The following returns default value defaultValue when attempting to look up missing key missingKey:

WITH {name:"Cristiano Ronaldo", country:"Portugal", dob:date("1985-02-05")} AS map
RETURN apoc.map.get(map, "missingKey", "defaultValue") AS output;

Results
Output
"defaultValue"