JAVA

arraylist insert at position

//Insert a value by using arrayName.add(index, value)
//Will not remove current element at index. Will simply move all elements to
//the right.
import java.util.ArrayList;
public class main{
  public static void main(String[] args){
   ArrayList<Integer> list = new ArrayList<Integer>();
   	list.add(0);
    list.add(1);
    list.add(2);
    list.add(3);
    list.add(4);
    list.add(5);
    list.add(0, 100);
    
    //enhanced for loop will print all elements of the ArrayList
    for(int element : list){
    System.out.print(list + ", ");
      }
    //Expected output: "100, 0, 1, 2, 3, 4, 5, "
  }
  
}

arraylist add at index

/* add(index, item to add); */
ArrayList<String> languages = new ArrayList<String>(); 
languages.add("PHP");
languages.add("JAVA");
languages.add("C#");
languages.add(2, "RUBY"); /* at index 2, add RUBY*/
ArrayList<int> numbers = new ArrayList<int>(); 
numbers.add(9);
numbers.add(14);
numbers.add(2);
numbers.add(1, 15); /* at index 1, add 15*/
/*
  After Execution:
  languages => PHP JAVA RUBY C#
  numbers => 9 15 14 2
*/

Add an element at a specified position in an ArrayList

import java.util.ArrayList;

class Main {
  public static void main(String[] args){

    // create ArrayList
    ArrayList<String> Websites = new ArrayList<>();

    // add() method without the index parameter
    Websites.add("Softhunt.net");
    Websites.add("Pythonprogramming.com");
    Websites.add("Tutorial.io");
    
    // add JavaScript.com at index 1
    Websites.add(0, "JavaScript.com");

    // add C++.net at index 3
    Websites.add(4, "C++.net");
    System.out.println("ArrayList: " + Websites);
  }
}

arraylist add at index

arrlist.add(2,25);