Vectors in Java

Vector Class

We may make resizable arrays comparable to the ArrayList class using the Vector class, which implements the List interface. A vector is similar to a dynamic collection that can modify its size, and we can utilise all the List interface's methods in vectors.

Vectors and the ArrayList are comparable. However, there are two differences:

• The vector is coordinated.
• There are several legacy methods in Java Vector that are not a part of a collections framework.

The syntax for Vector class

public class Vector<E>  extends Object<E>  implements List<E>, Cloneable, Serializable 

The syntax for the creation of vector

Vector<Type> vector = new Vector<>();

Example for vector creation

Vectorcreation.java

import java.io.*;
import java.util.*;
public class Vectorcreation
{
public static void main(String[] args) {
    // Integer type vector is created
        Vector<Integer> vector= new Vector<>();


        // String type vector is created
        Vector<String> vector1= new Vector<>();

}
}

Output

Constructors used in Vector class

1. vector()
   A vector of default size ten is created
2. vector(int initialCapacity)
   An empty vector is created, and the size will be zero with specified capacity and increment.
3. vector(int initialCapacity, int capacityincrement)
   An empty vector is created with specified capacity and increment value.
4. Vector( Collection<? extends E> c)
   Created a vector that contains elements of c

Methods in Vectors

1. Add elements to the vector

• add()
  It adds an element to the end of the given vector

• add(index, element)
  It adds described element at the preferred position

• addAll(vector)
  It adds a vector to a vector

Program for the addition of  elements to vectors

Vectorsadd.java

import java.util.Vector;
import java.io.*;


class Vectorsadd {
    public static void main(String[] args) {
        // Integer vector with name numbers is defined
        Vector<Integer> numbers= new Vector<>();


        //Use the add() method to add numbers 10 and 20 to the vector 
        numbers.add(10);
        numbers.add(20);
        System.out.println("Vector after adding 10 and 20 is : " +numbers);
        // Using index number
        numbers.add(2,50);
        System.out.println("Vector: " +numbers);


        // Using addAll()
        // adding one vector number to the vector primes
        Vector<Integer> primes = new Vector<>();
        primes.add(3);


        primes.addAll(numbers);
        System.out.println("New Vector: " + primes);
    }
}

Output

2. Accessing elements in the vector

To access elements of the vector, we use predefined methods of vector class such as get(index) and iterator methods.

1.get(index)

   It returns an element specified by the given index

Program for accessing elements of the vector using the get(index) method

AccessEle.java

import java.util.Vector;
class AccessEle {
    public static void main(String[] args) {
        Vector<String> cars= new Vector<>();
        cars.add("BMW");
        cars.add("Range Rover");
        cars.add("Ford");


        // Using get()
        String element = cars.get(2);
        System.out.println("Element at index 2: " + element);
    }
}

Output

2.iterator()

  It is used to access elements of vector sequentially

Program for accessing elements of the vector using the iterator method

AccessEle.java

import java.util.Vector;
import java.util.Iterator;
class AccessEle {
    public static void main(String[] args) {
        Vector<String> cars= new Vector<>();
        cars.add("BMW");
        cars.add("Range Rover");
        cars.add("Ford");
         // Using iterator()
        Iterator<String> iterate = cars.iterator();
        System.out.print("Vector: ");
        while(iterate.hasNext()) {
            System.out.print(iterate.next());
            System.out.print(", ");
    }
    }
}

Output

3. Removing elements in the vector

To remove some aspects from the vector

1. remove(index)

We can delete a particular index element from the vector using this method.

Program for removing elements of the vector using the remove(index) method

Remove.java

import java.util.Vector;
import java.util.Iterator;
class Remove {
    public static void main(String[] args) {
        Vector<String> cars= new Vector<>();
        cars.add("BMW");
        cars.add("Range Rover");
        cars.add("Ford");
        // Using remove(index) to remove element at index 1
        String element = cars.remove(1);
        System.out.println("Removed Element: " + element);
        System.out.println("New Vector: " + cars);
    }}

Output

2. clear()

Using this method, we can clear all elements from a particular vector.

Program for removing elements of vector using clear(index) method

Clear.java

import java.util.Vector;
import java.util.Iterator;
class Clear{
    public static void main(String[] args) {
        Vector<String> cars= new Vector<>();
        cars.add("BMW");
        cars.add("Range Rover");
        cars.add("Ford");


         // Using clear()
        cars.clear();
        System.out.println("Vector after clear(): " + cars);
    }
}

Output

Example program for vectors in Java

Example1.java

import java.util.*;  
public class Example1 {  
       public static void main(String args[]) {  
        //Create an empty Vector        
        Vector<Integer> v = new Vector<>();  
        //Add elements in the vector  
        v.add(10);  
        v.add(20);  
        v.add(30);  
        v.add(40);  
        v.add(50);  
        //Display the vector elements  
        System.out.println("Values in vector: " +v);  
        //use the remove() method to delete the first occurrence of an element  
        System.out.println("Remove first occurrence of element 20: "+v.remove((Integer)20));  
        System.out.println("Values in vector: " +v);  
        //Remove an element  at index 5
        v.removeElementAt(5);        
        System.out.println("Vector element after removal: " +v);  
// Hash code is printed
        System.out.println("Hash code of this vector = "+v.hashCode());  
        // we will get element at the specified index  
        System.out.println("Element at index 1 is = "+v.get(1));  
          }  
}  

Output