How to get the length of the 2D array in Java

Two dimensional array in java

To declare an 2D array in java we use the following syntax

Datatype [][] arrayName=new Datatype[rows][cols]

If you want to declare any primitive 2D array.

int [][] ages=new int[3][4];

double [][] prices=new double[4][4]

Array ages is a two-dimensional int array, it can store 3 rows and each row can contain 4 values (columns) total of 3*4=12 values.

similar price is a two-dimensional double array, it can store 4 rows and 4 columns total (4*4) 20 elements.

Two-dimensional array initialization

int[][] ages = {
            {1, 2, 3},
            {4, 5, 6},
            {7, 8, 9}
        };

        int[][] b = new int[2][2];
        b[0][0] = 1;
        b[0][1] = 2;
        b[1][0] = 3;
        b[1][1] = 4;

int[][] ages = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9}

};

int[][] b = new int[2][2];

b[0][0] = 1;

b[0][1] = 2;

b[1][0] = 3;

b[1][1] = 4;

above are the two-dimension array declared and initialized.

Length of an array in Java

Java array provides a variable length to find the length of a variable.4

to find the length of one dimension array we use following code

        int[] a={1,2,3,4,5,6};
        int length=a.length;
        System.out.println("Length of an array is "+length);

int[] a={1,2,3,4,5,6};

int length=a.length;

System.out.println("Length of an array is "+length);

One dimension array length is number of elements in array

Length of the 2D array in Java

In a two-dimensional array, java length is the number of rows in 2D array.

   public class ArrayEx {

    public static void main(String[] args) {

        int[][] ages = {
            {1, 2, 3},
            {4, 5, 6},
            {7, 8, 9}
        };

        int[][] b = new int[2][2];
        b[0][0] = 1;
        b[0][1] = 2;
        b[1][0] = 3;
        b[1][1] = 4;

        double[][] prices = {
            {12.33, 44.20, 54.06, 41.54, 32.44},
            {12.33},
            {},
            {32.22, 43.24, 54.22},
            {44.44, 53.43, 23.12}
        };
        System.out.println("Length of ages " + ages.length);
        System.out.println("Length of b " + b.length);
        System.out.println("Length of prices " + prices.length);

    }

}

public class ArrayEx {

public static void main(String[] args) {

int[][] ages = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9}

};

int[][] b = new int[2][2];

b[0][0] = 1;

b[0][1] = 2;

b[1][0] = 3;

b[1][1] = 4;

double[][] prices = {

{12.33, 44.20, 54.06, 41.54, 32.44},

{12.33},

{},

{32.22, 43.24, 54.22},

{44.44, 53.43, 23.12}

};

System.out.println("Length of ages " + ages.length);

System.out.println("Length of b " + b.length);

System.out.println("Length of prices " + prices.length);

}

Length of ages 3
Length of b 2
Length of prices 5

Length of ages 3

Length of b 2

Length of prices 5

To access each row length we can use the following code

   System.out.println("Length of ages[0] " + ages[0].length);
        System.out.println("Length of ages[1] " + ages[1].length);
        System.out.println("Length of ages[2] " + ages[2].length);
        System.out.println("Length of b[0] " + b[0].length);
        System.out.println("Length of b[1] " + b[1].length);
        System.out.println("Length of prices[0] " + prices[0].length);
        System.out.println("Length of prices[1] " + prices[1].length);
        System.out.println("Length of prices[2] " + prices[2].length);
        System.out.println("Length of prices[3] " + prices[3].length);
        System.out.println("Length of prices[4] " + prices[4].length);

System.out.println("Length of ages[0] " + ages[0].length);

System.out.println("Length of ages[1] " + ages[1].length);

System.out.println("Length of ages[2] " + ages[2].length);

System.out.println("Length of b[0] " + b[0].length);

System.out.println("Length of b[1] " + b[1].length);

System.out.println("Length of prices[0] " + prices[0].length);

System.out.println("Length of prices[1] " + prices[1].length);

System.out.println("Length of prices[2] " + prices[2].length);

System.out.println("Length of prices[3] " + prices[3].length);

System.out.println("Length of prices[4] " + prices[4].length);

Length of ages[0] 3
Length of ages[1] 3
Length of ages[2] 3
Length of b[0] 2
Length of b[1] 2
Length of prices[0] 5
Length of prices[1] 1
Length of prices[2] 0
Length of prices[3] 3
Length of prices[4] 3

Length of ages[0] 3

Length of ages[1] 3

Length of ages[2] 3

Length of b[0] 2

Length of b[1] 2

Length of prices[0] 5

Length of prices[1] 1

Length of prices[2] 0

Length of prices[3] 3

Length of prices[4] 3