2 Ways To Combine Arrays Inward Coffee – Integer, String Array Re-Create Example

There are multiple ways to combine or bring together 2 arrays inward Java, both for primitive similar int array together with Object e.g. String array. You tin fifty-fifty write your ain combine() method which tin role System.arrayCopy() to re-create both those array into the tertiary array. But beingness a Java developer, I start looked inward JDK to detect whatsoever method which concatenates 2 arrays inward Java. I looked at java.util.Arrays class, which I convey used before to compare 2 arrays together with print arrays inward Java, but didn't detect a straight agency to combine 2 arrays. Then I looked into Apache Commons, ArrayUtils class, together with bingo, it has several overloaded method to combine int, long, float, double or whatsoever Object array. Later I too flora that Guava ,earlier known every bit Google collections too has a bird ObjectArrays inward com.google.common.collect the package, which tin concatenate 2 arrays inward Java. It's ever expert to add together Apache commons together with Guava, every bit supporting library inward Java project, they convey lots of supporting classes, utility together with method, which complements rich Java API. In this Java programming tutorial, nosotros volition come across an instance of these 2 ways to combine, bring together or concatenate 2 arrays inward Java together with volition write a method inward substance Java to concatenate 2 int arrays inward Java.

In this Java example, nosotros volition start combine 2 int arrays together with then, 2 String arrays. We volition role Apache common ArrayUtils.addAll() method to combine 2 integer arrays inward Java together with Google's Guava library to bring together 2 String array inward Java. 

Though nosotros tin too role ArrayUtils to combine object arrays, every bit it provides an overloaded method for every type inward Java, I convey listed Guava instance for the sake of information. Open root libraries should hold upward preferred, if you lot are doing a existent projection together with writing production code, because of testing payoff they provide. 

If you lot are combining arrays exactly every bit part of programming exercise or homework than you lot ameliorate endeavor to write a method yourself, to bring together 2 arrays

How to combine Array inward Java - Example

integer arrays for simplicity. This is too a expert chance to learn, how to role System.arrayCopy() method  in Java, which is the best agency to re-create i array to around other inward Java.

import com.google.common.collect.ObjectArrays;

import java.util.Arrays;

import org.apache.commons.lang.ArrayUtils;

/**

 * Java programme to combine 2 arrays inward Java. In this Java example

 * start nosotros convey concatenated 2 int arrays together with afterwards 2 String arrays.

 * First array combine examples role Apache common ArrayUtils, minute array

 * bring together instance uses Guava's ObjectArrays together with the final array concatenates instance uses JDK.

 *

 * @author Javin Paul

 */

public bird CombineArrayJava {

    public static void main(String args[]) {

      

        int [] start = {1,2,3, 4};

        int [] minute = {5,6,7,8};

      

        // combine 2 arrays inward Java using Apache common ArrayUtils

        int [] combined = ArrayUtils.addAll(first, second);

     

        System.out.println("First array : " + Arrays.toString(first));

        System.out.println("Second array : " + Arrays.toString(second));

        System.out.println("Combined array : " + Arrays.toString(combined));

    

        String [] i = {"a", "b", "c"};

        String [] 2 = {"d", "e"};

      

        //joining array inward Java using Guava library

        String [] joined = ObjectArrays.concat(one, two, String.class);

        System.out.println("Joined array : " + Arrays.toString(joined));

      

        //JDK agency to combine 2 array inward Java

        int[] array1 = {101,102,103,104};

        int[] array2 = {105,106,107,108};

        int[] concatenate = combine(array1, array2);

        System.out.println("concatenated array : " + Arrays.toString(concatenate));

      

    }

  

 

    public static int[] combine(int[] a, int[] b){

        int length = a.length + b.length;

        int[] consequence = new int[length];

        System.arraycopy(a, 0, result, 0, a.length);

        System.arraycopy(b, 0, result, a.length, b.length);

        return result;

    }

  

}

Output:

First array : [1, 2, 3, 4]

Second array : [5, 6, 7, 8]

Combined array : [1, 2, 3, 4, 5, 6, 7, 8]

Joined array : [a, b, c, d, e]

concatenated array : [101, 102, 103, 104, 105, 106, 107, 108]

Just continue inward hear that, hither nosotros are combining 2 arrays, we are non merging arrays i.e. if both array contains same element, they volition hold upward repeated inward combined array. You tin concatenate or combine 2 arrays of dissimilar length every bit shown inward minute example, It's non necessary to hold upward same length but they must hold upward of same type, i.e. you lot tin non combine String array to int array inward Java. In gild to role Apache common together with Google Guava you lot tin include them every bit dependency inward Maven projection or you lot tin exactly add together their respective JAR into classpath to compile this Java program.

That's all on How to combine 2 arrays inward Java. We convey seen, an instance of combining or concatenating 2 int arrays every bit good every bit 2 String arrays. We convey used a library to do our job, which you lot should do if you lot are using it inward your production code. If you lot are doing this every bit Java programming exercise, together with then you lot need to write a method to combine 2 arrays yesteryear using criterion JDK. You demand to do novel Array amongst length equal to the total of the length of the private array together with than you lot at that topographic point role for loop or System.arrayCopy() method to re-create private array into combined array, every bit shown inward our tertiary array concatenation instance inward Java.

Further Learning
Data Structures together with Algorithms: Deep Dive Using Java
answer)

Difference betwixt a binary tree together with binary search tree? (answer)

How to contrary a linked listing inward Java using iteration together with recursion? (solution)

How to contrary an array inward house inward Java? (solution)

How to detect all permutations of a String inward Java? (solution)

How to contrary a String inward house inward Java? (solution)

How to take duplicate elements from an array without using Collections? (solution)

Top five Books on Data Structure together with Algorithms for Java Developers (books)

Top five books on Programming/Coding Interviews (list)