Friday, February 20, 2015

Array List Example


import java.util.*;

 

public class ArrayListExamples {

 

    public static void main(String args[]) {

        // Creating an empty array list

        ArrayList<String> list = new ArrayList<String>();

 

        // Adding items to arrayList

        list.add("Item1");

       list.add("Item2");

        list.add(2, "Item3"); // it will add Item3 to the third position of

                                // array list

        list.add("Item4");

 

        // Display the contents of the array list

        System.out.println("The arraylist contains the following elements: "

                + list);


        // Checking index of an item

       int pos = list.indexOf("Item2");

        System.out.println("The index of Item2 is: " + pos);

 

       // Checking if array list is empty

        boolean check = list.isEmpty();

       System.out.println("Checking if the arraylist is empty: " + check);

 

        // Getting the size of the list

        int size = list.size();

        System.out.println("The size of the list is: " + size);

 

       // Checking if an element is included to the list

        boolean element = list.contains("Item5");

        System.out

                .println("Checking if the arraylist contains the object Item5: "

                        + element);

 

        // Getting the element in a specific position

        String item = list.get(0);

        System.out.println("The item is the index 0 is: " + item);

 

        // Retrieve elements from the arraylist

 

        // 1st way: loop using index and size list

        System.out

                .println("Retrieving items with loop using index and size list");

        for (int i = 0; i < list.size(); i++) {

            System.out.println("Index: " + i + " - Item: " + list.get(i));

        }

 

        // 2nd way:using foreach loop

        System.out.println("Retrieving items using foreach loop");

        for (String str : list) {

            System.out.println("Item is: " + str);

        }

 

        // 3rd way:using iterator

        // hasNext(): returns true if there are more elements

        // next(): returns the next element

        System.out.println("Retrieving items using iterator");

        for (Iterator<String> it = list.iterator(); it.hasNext();) {

            System.out.println("Item is: " + it.next());

        }

 

        // Replacing an element

        list.set(1, "NewItem");

        System.out.println("The arraylist after the replacement is: " + list);

 

        // Removing items

        // removing the item in index 0

        list.remove(0);

 

        // removing the first occurrence of item "Item3"

        list.remove("Item3");

 

        System.out.println("The final contents of the arraylist are: " + list);

 

        // Converting ArrayList to Array

        String[] simpleArray = list.toArray(new String[list.size()]);

        System.out.println("The array created after the conversion of our arraylist is: "

                        + Arrays.toString(simpleArray));
    }

}


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