How does array.sort work with multidimensional arrays?

Question

I've been looking around on the internet trying to find out how to sort a multidimensional array by column and i found a way that works but I'm not sure exactly how it works. Can someone explain it to me?

Arrays.sort(data, (int[] num1, int[] num2) ->
    Integer number1 = num1[1];
    Integer number2 = num2[1];
    return number2.compareTo(number1);
});

in this care the code sorts the array [][] in descending order by the second column.

This code is for Java 8 and uses lambda expressions. You are missing {. — PM 77-1
– PM 77-1, Commented Aug 6, 2015 at 18:07

Eran · Accepted Answer · 2015-08-06 18:03:35Z

3

A two dimensional array is an array whose elements are arrays (int[] in your case). Therefore, in order to sort such an array, you should supply a comparator that compares int[] objects. This is exactly what the lambda expression in your code snippet does. It accepts two int[] objects and determines their relative order by comparing the elements at the second position (i.e. index 1) of the two arrays.

The lambda expression is a feature added in Java 8. It allows you to supply an implementation to a functional interface (which is an interface with a single method, such as Comparator<int[]>, whose single method is int compare (int[] first, int[] second)) without most of the syntax required for anonymous class instances.

answered Aug 6, 2015 at 18:03

Eran

395k57 gold badges726 silver badges793 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How does array.sort work with multidimensional arrays?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related