Here’s a simple utility method that will return the set of values for a given field within a list of records. It’s useful, for example, when you need to find all the Accounts referenced by a list of Contacts. Or to find the unique Status values used by a list of Cases.
/**
* @description return the unique values for a given field in a list of
* records. Null is not included.
* @param objects the list of records
* @param field values from this field will be returned
* @return set of values; no null
*/
public static Set<Object> getFieldValues(SObject[] objects, SObjectField field) {
Set<Object> result = new Set<Object>();
if (null != objects) {
for (SObject o : objects) {
result.add(o.get(field));
}
result.remove(null);
}
return result;
}And here’s an easily-derived variation that saves you a little typing when getting the set of IDs from a list:
/**
* @description return the unique Ids in a list of records.
* @param objects the list of records
* @return set of Ids; no null
*/
public static Set<Id> getIds(SObject[] objects) {
return (Set<Id>)getFieldValues(objects, Case.Id);
}