ArrayList in java
ArrayList is a collection of data. The main reason for creating ArrayList, In java array data stored in specified size. If i want stored the data in dynamic size.I can't use array.
Add
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<Integer> num = new ArrayList<Integer>();
num.add(1);
num.add(2);
num.add(3);
System.out.println(num);
}
}
Output
[1, 2, 3]
Remove
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<Integer> num = new ArrayList<Integer>();
num.add(1);
num.add(2);
num.add(3);
num.remove(0);
System.out.println(num);
}
}
Output
[2, 3]
Size
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<Integer> num = new ArrayList<Integer>();
num.add(1);
num.add(2);
num.add(3);
System.out.println(num.size());
}
}
Output
3
Clear
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<Integer> num = new ArrayList<Integer>();
num.add(1);
num.add(2);
num.add(3);
num.clear();
System.out.println(num);
}
}
Output
[]
Get
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<Integer> num = new ArrayList<Integer>();
num.add(1);
num.add(2);
num.add(3);
System.out.println(num.get(1));
}
}
Output
2
Set
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<Integer> num = new ArrayList<Integer>();
num.add(1);
num.add(2);
num.add(3);
num.set(1,99);
System.out.println(num);
}
}
Output
[1, 99, 3]
print each element:
method-1
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<Integer> num = new ArrayList<Integer>();
num.add(1);
num.add(2);
num.add(3);
for (int i=0;i<num.size();i++)
{
System.out.println(num.get(i));
}
}
}
Output
1 2 3
method-2
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<Integer> num = new ArrayList<Integer>();
num.add(1);
num.add(2);
num.add(3);
for (int i:num)
{
System.out.println(i);
}
}
}
Output
1 2 3
String:
Add
import java.util.ArrayList;
public class Main
{
public static void main(String[] args)
{
ArrayList<String> name = new ArrayList<String>();
name.add("jack");
name.add("stark");
name.add("steve");
System.out.println(name);
}
}
Output
[jack, stark, steve]