Help With ArrayList
Hi All,
I want to compare elements of two arraylist 's wherein one Arraylist is
Arraylist1 = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
and the other arraylist is
Arraylist2 = [1, 2, 6, 49, 9]
and then my output should be
output:
Arraylist2 = [1,2,6,9]
i.e. It should just retain the common elements present in the Arraylist1 in Arraylist2
I dont know much about collections ...
I have written a code wherein I have created two arraylists but I dont know how to proceed further,....
MyCode:
import java.util.ArrayList;
publicclass ArrayListExample
{
publicstaticvoid main(String[] args)
{
ArrayList Arraylist1 =new ArrayList();
for (int i = 0; i < 10; i++)
{
parentList.add(i);
}
System.out.println(Arraylist1);
ArrayList Arraylist2 =new ArrayList();
childList.add(1);
childList.add(2);
childList.add(6);
childList.add(49);
childList.add(9);
System.out.println(Arraylist2);
}
}
Will this statement help...
I Could just come up with this..
if(Arraylist1.equals(Arraylist2))
Please help
Hi,
This code is answer for your question. As suggested by Daniel you can even make use of ArrayList method contains.
import java.util.ArrayList;
public class ArrayListExample
{
public static void main(String[] args)
{
//Declaration of 3 ArrayList
ArrayList Arraylist1 = new ArrayList();
ArrayList Arraylist2 = new ArrayList();
ArrayList Arraylist3 = new ArrayList();
//Adding elements to Arraylist1
Arraylist1.add("1");
Arraylist1.add("2");
Arraylist1.add("3");
Arraylist1.add("4");
Arraylist1.add("5");
Arraylist1.add("6");
Arraylist1.add("7");
Arraylist1.add("8");
Arraylist1.add("9");
Arraylist1.add("0");
System.out.println("Fist ArrayList "+Arraylist1);
//Adding elements to Arraylist2
Arraylist2.add("1");
Arraylist2.add("2");
Arraylist2.add("6");
Arraylist2.add("49");
Arraylist2.add("9");
System.out.println("Second ArrayList "+Arraylist2);
//Size of ArrayList1
int arrayList1_Length = Arraylist1.size();
//Size of ArrayList2
int arrayList2_Length = Arraylist2.size();
//compare logic
for (int i=0;i<arrayList1_Length;i++)
{
Object arrayList1_obj = Arraylist1.get(i);
for (int j=0;j<arrayList2_Length; j++)
{
Object arrayList2_obj = Arraylist2.get(j);
if (arrayList2_obj.equals(arrayList1_obj))
{
Arraylist3.add(arrayList2_obj);
}
}
}
System.out.println(Arraylist3);
}
}
[code]
[/code]
-Kiran>
Thanks a lot..
I tried your code it works ..
I found a another way to do it.. by using retainAll() method.
Thanks a lot..
import java.util.ArrayList;
public class MainArrayListExample
{
public static void main(String[] args)
{
ArrayList parentList = new ArrayList();
for (int i = 0; i < 50; i++)
{
parentList.add(i);
}
System.out.println(parentList);
ArrayList childList = new ArrayList();
childList.add(1);
childList.add(2);
childList.add(25);
childList.add(33);
childList.add(57);
childList.add(49);
childList.add(35);
System.out.println(childList);
ArrayList listInBoth = new ArrayList(parentList);
listInBoth.retainAll(childList);
System.out.println(listInBoth);
}
}
