Question

On my quest learning Java I come across one doubt.

For sorting a unidimensional array we can use Arrays.sort() but if I want to sort a bidimensional array based on three columns? Is there any option to d that or do I have to code it for my self (something like three nested loops)?

Here is an example input:

13  2   28  36  
1   4   56  17  
4   2   5   40  
2   4   41  55  
9   5   48  12  
19  2   25  12  
20  5   13  8   
15  3   51  30  
12  5   39  59  
17  3   56  40  
3   1   56  46  
7   3   28  51  
8   5   14  58  
5   3   34  15  
14  4   53  2   
18  4   38  57  
6   2   16  25  
16  3   17  13  
10  5   41  33  
11  1   13  57  

Columns are int and this is stored in an array of ints.

I wanna sort by column 2, if equal numbers are found, then sort by column 3 and finally, if equals found, sort by column 3.

The output should be this:

11  1   13  57  
3   1   56  46  
4   2   5   40  
6   2   16  25  
19  2   25  12  
13  2   28  36  
16  3   17  13  
7   3   28  51  
5   3   34  15  
15  3   51  30  
17  3   56  40  
18  4   38  57  
2   4   41  55  
14  4   53  2   
1   4   56  17  
20  5   13  8   
8   5   14  58  
12  5   39  59  
10  5   41  33  
9   5   48  12  

Is there a simple way for doing this?
Remember that I’m new at Java.

regards,

Favolas

Answer 1

Simple use Comparator and use Arrays.sort(arr, comparator);