I've got a Map that I want to iterate over and increment some of the field values of the account. Is it possible to simply set one field value or do I need to instantiate a new Account with similar values and put that into the map to replace the existing values?

Map<Id,Account> accMap = new Map<Id,Account>([Select Id, Field1, Field2 From Account]);
for(Id key : accMap.keyset()){
    accMap.get(key).Field1+1; //Can I do something like this or some similar syntax?

    //Or do I have to put a "new" entry into the Map like this?
    Account a = new Account(
        Id = key,
        Field1 = accMap.get(key).Field1+1,
        Field2 = accMap.get(key).Field2

The second option would certainly work, but would be a pain to maintain if I'm incrementing multiple fields at the same time.

1 Answer 1


You can do:

Account a = accMap.get(key);
a.Field1 += 1;
a.Field2 += 1;

so you don't need to replace the object.

Or more simply just use the values from the map:

for(Account a : accMap.values()) {
    a.Field1 += 1;
    a.Field2 += 1;

If any of the fields might be null you need to check for that e.g.:

a.Field1 = a.Field1 != null ? a.Field1 + 1 : 1;

or better add a method that performs that logic.

(A special case where a new object is needed is if you want to do an update in an "after" trigger.)

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