Selasa, 21 April 2015

JAVA - How To Use ArrayList In Java NetBeans

Java - How To Display Data From An ArrayList In Java

In this java Collection tutorial we will see How To Use An ArrayList.

1: how to create a ArrayList

2: how to dispaly data from it

3: how to clear all elements from it
And More.......

*Java Courses : Java Complete Course
Java Swing Course

Source Code:

package javaapp;
import java.util.ArrayList;
public class Woirk {

public static void main(String[] args){

ArrayList list = new ArrayList();

//add data to the ArrayList
list.add(1);
list.add("string");
list.add('c');
list.add(false);
list.add(10.23f);
list.add(null);

System.out.println("display data from Arraylist");

displaydata(list);

System.out.println("______ Remove elements from ArrayList");

list.remove(3);
displaydata(list);

System.out.println("________ Clear All elements from ArrayList");

list.clear();
displaydata(list);
}

//create a methode to dispaly values from an arraylist
public static void displaydata(ArrayList l){
for(int i = 0; i < l.size(); i++){
System.out.println(l.get(i));
}
}
}

////////////// OUTPUT:

display data from Arraylist
1
string
c
false
10.23
null
______ Remove elements from ArrayList
1
string
c
10.23
null
________ Clear All elements from ArrayList

Another Source Code:

package javaapp;

import java.util.List;
import java.util.ArrayList;

public class Woirk {

public static void main(String[] args){

ArrayList list = new ArrayList();

ArrayList<Integer> list2 = new ArrayList<Integer>();
list2.add(100);
list2.add(200);
list2.add(300);
list2.add(400);
list2.add(500);

//add elements to the list
for(int i = 0; i < 10; i++){
list.add(i);
}

//add element to a specific position in ArrayList
list.add(list.size()-1,99999);

/*
Insert all elements in The liste2 in list
starting at the specific positionc (in this example 5)
*/
list.addAll(5,list2);

//display ArrayList data
System.out.println(list);

//cast ArrayList to Object[]
Object[] obj = list.toArray();
System.out.println("Start Of ToArray");
for(Object o : obj)
System.out.print(" - "+o);
System.out.println("\n End Of ToArray");

//clone or copy the list elements to another list
ArrayList li = new ArrayList();
li = (ArrayList<Integer>) list.clone();

System.out.println("The List Clone Start.......");

System.out.println(li);

System.out.println("The List Clone End.......");

/*
get a sublist between to index
fromIndex inclusive, and toIndex exclusive
*/
List<Integer> sublist = list.subList(10, 13);

System.out.println("The subList Start.......");

System.out.println(sublist);

System.out.println("The SubList End.......");

// return the index of the element
//-1 if not exist
int index = list.indexOf(99999);
System.out.println("The Index Of 99999 Is: "+ index);

//if the element exist = true, if not = false
boolean test = list.contains(300);
System.out.println("the list contains 300? => "+test);

//clear all the elemnts in the arraylist

System.out.println("list size before the clear: "+list.size());
list.clear();
System.out.println("list size after the clear: "+list.size());

//see if the list is empty
System.out.println("Check if the list is empty: "+list.isEmpty());
}

}

////////////// OUTPUT:

[0, 1, 2, 3, 4, 100, 200, 300, 400, 500, 5, 6, 7, 8, 99999, 9]
Start Of ToArray
- 0 - 1 - 2 - 3 - 4 - 100 - 200 - 300 - 400 - 500 - 5 - 6 - 7 - 8 - 99999 - 9
End Of ToArray
The List Clone Start.......
[0, 1, 2, 3, 4, 100, 200, 300, 400, 500, 5, 6, 7, 8, 99999, 9]
The List Clone End.......
The subList Start.......
[5, 6, 7]
The SubList End.......
The Index Of 99999 Is: 14
the list contains 300? => true
list size before the clear: 16
list size after the clear: 0

Check if the list is empty: true

see also the Hashtable
see also the LinkedList