Two Dimensional Array in Java

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From the previous article Java Array Basics, we understand that an array is like a container that can hold a certain number of values. In this article, we will learn what is a two-dimensional array, how to initialize and access a two-dimensional array with examples.
In the Java programming language, a multidimensional array is an array whose components are themselves arrays.

Two Dimensional Array Simple Example

class MultiDimArrayDemo {
                                                                                 
    public static void main(String[] args){
        String[][] names = {
            {"Mr. ","Mrs. ","Ms. "},
            {"Smith","Jones"}};
 
        // Mr. Smith
        System.out.println(names[0][0] +
                           names[1][0]);
        // Ms. Jones
        System.out.println(names[0][2] + 
                           names[1][1]);
    }
}
Output:
Mr. Smith
Ms. Jones
The following code prints the array's size to standard output:
 System.out.println(anArray.length);
Let’s look at few examples of defining java two-dimensional array or 2d array.

Java Two Dimensional Array of primitive type

Let's create an array of int arrays of 2 row and 3 columns.
// an array of int arrays of 2 row and 3 columns
int[][] twoDimArray = new int[2][3];
for (int i = 0; i < twoDimArray.length; i++) {
 for (int j = 0; j < twoDimArray[i].length; j++) {
  twoDimArray[i][j] = j;
  System.out.print(twoDimArray[i][j] + " ");
 }
 System.out.println("");
}
Output:
0 1 2 
0 1 2

Java Two Dimensional Array of Objects

Let's create an array of String arrays of 3 rows and 4 columns.
// an array of String arrays of 3 rows and 4 columns
String[][] arrStr = new String[3][4];
for (int i = 0; i < arrStr.length; i++) {
 for (int j = 0; j < arrStr[i].length; j++) {
  arrStr[i][j] = "Str" + j;
  System.out.print(arrStr[i][j] + " ");
 }
 System.out.println("");
}
Output:
Str0 Str1 Str2 Str3 
Str0 Str1 Str2 Str3 
Str0 Str1 Str2 Str3

Shortcut Syntax to Create and Initialize a Two Dimensional Array

Shortcut syntax to create and initialize an array:
// creating and initializing two dimensional int array with shortcut
// syntax
int[][] arrInt = { { 1, 2,3 }, { 3, 4, 5 } };
for (int i = 0; i < arrInt.length; i++) {
 for (int j = 0; j < arrInt[i].length; j++) {
  System.out.print(arrInt[i][j] + " ");
 }
 System.out.println("");
}

Complete Two Dimensional Array Source Code Example

/**
 * This class will show how to initialize two dimensional array
 * @author javaguides.net
 *
 */
public class TwoDimentionalArray {

 public static void main(String[] args) {

  // an array of int arrays of 2 row and 3 columns
  int[][] twoDimArray = new int[2][3];
  for (int i = 0; i < twoDimArray.length; i++) {
   for (int j = 0; j < twoDimArray[i].length; j++) {
    twoDimArray[i][j] = j;
    System.out.print(twoDimArray[i][j] + " ");
   }
   System.out.println("");
  }

  // an array of String arrays of 3 rows and 4 columns
  String[][] arrStr = new String[3][4];
  for (int i = 0; i < arrStr.length; i++) {
   for (int j = 0; j < arrStr[i].length; j++) {
    arrStr[i][j] = "Str" + j;
    System.out.print(arrStr[i][j] + " ");
   }
   System.out.println("");
  }

  // creating and initializing two dimensional int array with shortcut
  // syntax
  int[][] arrInt = { { 1, 2,3 }, { 3, 4, 5 } };
  for (int i = 0; i < arrInt.length; i++) {
   for (int j = 0; j < arrInt[i].length; j++) {
    System.out.print(arrInt[i][j] + " ");
   }
   System.out.println("");
  }
 }

}

References

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