How to sort two dimensional array in Java?

Question

I have a two dimensional double array. I need to sort my based column 1 in descending order. How can I sort my two dimensional array in descending order.

Sample data and code are the following:

package mypro.com;

public class SortDoubleArrary {    
    public static void main(String agrs[]) throws Exception{

        double[][] testdatset=new double[5][2];

        testdatset[0][0]=20.0;              
        testdatset[0][1]=0.20;

        testdatset[1][0]=100.0;             
        testdatset[1][1]=0.50;              

        testdatset[2][0]=10.0;              
        testdatset[2][1]=0.95;

        testdatset[3][0]=220.0;             
        testdatset[3][1]=0.35;              

        testdatset[4][0]=140.0;
        testdatset[4][1]=0.10;        
    }  
}

Expected output looks like the following

 10.0    0.95
 100.0   0.5
 220.0   0.35
 20.0    0.2
 140.0   0.1

Answer 1

There is an overloaded sort method in java.util.Arrays class which takes two arguments: the array to sort and a java.util.Comparator object.

You can add the following lines of code with your program to get the expected result.

import java.util.Arrays;
import java.util.Comparator;


Arrays.sort(testdatset, new Comparator<double[]>() {      
        @Override
        public int compare(double[] o1, double[] o2) {
            return Double.compare(o2[1], o1[1]);
        }
    });