Adding list of values/Records to Key using Apex Map

 

We can add records to the list directly using the "add" method but while coming to add list or values/records to a key we need to use map<id,list<subject>>.

Below is the sample code:

Map<Id, List<user>> mapUserRoleToUsers = new Map<Id, List<user>>();

for(User userRec : [SELECT UserRoleId FROM User LIMIT 50000]) {

//Checks if the User Role Id is already added to key or not 

if(mapUserRoleToUsers.containsKey(userRec.UserRoleId)) {

List<user> usersRecs = mapUserRoleToUsers.get(userRec.UserRoleId);

usersRecs.add(userRec);

mapUserRoleToUsers.put(userRec.UserRoleId, usersRecs);

} else {

mapUserRoleToUsers.put(userRec.UserRoleId, new List<user> { userRec });

}

}

From the above code you can get all the user records based on the user role id.