SET in Apex Salesforce Introduction

SET in Apex Salesforce Introduction 

Set: 
It is an unordered collection of elements where elements can be of any data type.Primitive types, and built – in apex types. 

1. Set don’t allow the duplicate values.
2. Insertion order is not preserved in the set. 
3. It grows dynamically at run time. 

Ex:  
          Set <string> names = new set<string> (); 
          Set <account> acc = new set <account> (); 
          Set <costumer – c> my costumers = new set <costumer—c> (); 
Public void add (object) // this method will add elements to the set. 
          Set <string> names = new set<string> (); 
          name. add (‘one’);
          name. add (‘two’);
          name. add (‘one’); 

Note: set will not allow duplicates, but if we insert it will not raise any error it will not takes values 

Public void add all (list) //this method will add all elements to the set. 
  
List <string> my list = new list <string> (); 
           My list. add (‘one’);
           My list. add (‘two’); 
Set<string> my names = new set <string> (); 
           My names. add (‘Sam’);
           My names. add (my list); 
Public integer size ()// this method will return no. of elements in the set.
           Set <string> names = new set <string> ();
           names. add (‘one’); 
           names. add (‘two’);
           names. add (‘one’); 

 Integer my size = names. size (); // this will return 3 and stored to my size variable.

Public void removes (integer index)// this method will remove the elements at the specified index. 
             names. remove (1);