Data commit

Task/Set/Apex/set.apex

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+public class MySetController{
+    public Set<String> strSet {get; private set; }
+    public Set<Id> idSet {get; private set; }
+
+    public MySetController(){
+        //Initialize to an already known collection.  Results in a set of abc,def.
+        this.strSet = new Set<String>{'abc','abc','def'};
+
+        //Initialize to empty set and add in entries.
+        this.strSet = new Set<String>();
+        this.strSet.add('abc');
+        this.strSet.add('def');
+        this.strSet.add('abc');
+        //Results in {'abc','def'}
+
+        //You can also get a set from a map in Apex. In this case, the account ids are fetched from a SOQL query.
+        Map<Id,Account> accountMap = new Map<Id,Account>([Select Id,Name From Account Limit 10]);
+        Set<Id> accountIds = accountMap.keySet();
+
+        //If you have a set, you can also use it with the bind variable syntax in SOQL:
+        List<Account> accounts = [Select Name From Account Where Id in :accountIds];
+
+        //Like other collections in Apex, you can use a for loop to iterate over sets:
+        for(Id accountId : accountIds){
+            Account a = accountMap.get(accountId);
+            //Do account stuffs here.
+        }
+    }
+}