Java Program to Convert Vector to Array

Java vector to array – Java Program to Convert Vector to Array

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Java vector to array: In the previous article, we have seen Java Program to Convert an Array into Collection

In this article we are going to see how to convert vector to array using Java programming language.

Java Program to Convert Vector to Array

Array:

Convert vector to array: Array is a data structure which stores a fixed size sequential collection of values of single type. Where with every array elements/values memory location is associated. Each array elements have it’s own index where array index starts from 0.

In Array set of variables referenced by a single variable name and it’s array index position. It is also called as a container object which contains elements of similar type.

Declaration of an array:

dataType[] arrayName; (or)                              //Declaring an array
dataType []arrayName; (or)
dataType arr[];

Instantiation of an Array:

arrayName = new datatype[size];                    //Allocating memory to array

Combining both Statements in One:

dataType[] arrayName = new dataType[size] //Declaring and Instantiating array

Initialization of an Array:

arrayName[index-0]= arrayElement1             //Initializing the array

...

arrayName[index-s]= arrayElementS

Combining all Statements in One:

dataType arrayName[ ]={e1,e2,e3};               //declaration, instantiation and initialization

Vector:

vector.toarray: Vector is a class which implements the List Interface. It is commonly used data structure as it allows to create resizable arrays. Means while arrays are static in nature, vector can grow or shrink its’ size depending on elements. While elements will be added into vector it can grow its’ size and while elements will be removed vector can reduce its size.

Let’s see different ways to convert vector to array.

Method-1: Java Program to Convert Vector to Array By Using toArray() Method and Arrays.copyOf() Method

Approach:

  1. Get the Vector.
  2. Convert the Vector to Object array using toArray() method.
  3. Convert the Object array to desired type array using Arrays.copyOf() method.
  4. Return the print the Array.

Program:

import java.util.*;

public class Main 
{
    
    public static void main(String args[]) 
    {
        // Creating vector
        Vector<String> vec = new Vector<String>();

        // Adding elements to the vector
        vec.add("J");
        vec.add("a");
        vec.add("v");
        vec.add("a");

        // Print the Vector
        System.out.println("Vector: " + vec);

        // Converting Vector to Object Array
        Object[] objArray = convertVectorToArray(vec);

        // Convert Object[] to String[]
        String[] arr = Arrays.copyOf(objArray, objArray.length, String[].class);
        // Print the String Array
        System.out.println("Array: " + Arrays.toString(arr));
    }

    // Function to convert Vector to Array
    public static <T> Object[] convertVectorToArray(Vector<T> vec) 
    {

        // Converting Vector to Array
        Object[] arr = vec.toArray();

        return arr;
    }
}


Output:

Vector: [J, a, v, a]
Array: [J, a, v, a]

Method-2: Java Program to Convert Vector to Array By Using toArray() Method

Approach:

  1. Created a Vector String type.
  2. Added elements into Vector using add(E) method.
  3. Convert the Vector to Array using toArray(new String[vector.size()]).

Program:

import java.util.*;

public class Main
{
    public static void main(String args[])
    {
        // Creating vector
        Vector<String> vec = new Vector<String>();

        // Adding elements to the vector
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the number of elements: ");
        int n = sc.nextInt();
        sc.nextLine(); // to consume the newline character
        System.out.println("Enter the elements: ");
        for (int i = 0; i < n; i++) 
        {
            vec.add(sc.next());
        }

        // Print the Vector
        System.out.println("Vector: " + vec);

        // Converting Vector to String Array
        String[] arr = vec.toArray(new String[vec.size()]);

        // Print the String Array
        System.out.println("Array: " + Arrays.toString(arr));
    }

}

Output:

Enter the number of elements: 4
Enter the elements: 
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Vector: [Btech, Geeks, Best, Platform]
Array: [Btech, Geeks, Best, Platform]

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