count group size in 2d array java code example

Example 1: how to get the dimensions of a 2d array in java

public class Main {
  public static void main(String[] args) {
    int[][] test = new int[10][4];
    int rows = test.length;
    int coloumns = test[0].length;
    System.out.println(rows);
    System.out.println(coloumns);
  }
}

Example 2: java length of matrix

public static void main(String[] args) {

    int[][] foo = new int[][] {
        new int[] { 1, 2, 3 },
        new int[] { 1, 2, 3, 4},
    };

    System.out.println(foo.length); //2
    System.out.println(foo[0].length); //3
    System.out.println(foo[1].length); //4
}