Java: Sorting a 2D array based on the second column's values

Question

I'm using Java and I have an int[][] array like so:

[ 65][  4]  
[108][ 47]  
[ 32][279]  
[103][ 26]  
[111][138]  
[100][ 63]  
[112][ 33] ...etc.

And I need to sort from least to greatest, based on the second column's values. I tried this code, also found on this website:

    print(myArray);
    System.out.println("==========");

    Arrays.sort(myArray, new Comparator<int[]>() {
        @Override
        public int compare(int[] int1, int[] int2)
        {
            Integer number1 = int1[1];
            Integer number2 = int2[1];
            return number1.compareTo(number2);
        }
    });

    print(myArray);

Where my print method is as follows:

public static void print(int[][] array) {
    int k = 0;
    while (array[k][0] != 0) {
        System.out.println("[" + array[k][0] + "][" + array[k][1] + "]");
        k++;
    }
}

It just doesn't seem to print the second time, no matter what. I'm just not sure what I'm doing wrong here. Hopefully it's just an easy fix :)

What are letter1 and letter2 in the compare(...) method? — Sergey Kalinichenko
– Sergey Kalinichenko, Commented Apr 9, 2012 at 15:43
possible duplicate of How do i sort a simple integer 2 dimensional array? — Brian Roach
– Brian Roach, Commented Apr 9, 2012 at 15:43
Probably a typo. His original application is likely sorting arrays of characters. — Alain
– Alain, Commented Apr 9, 2012 at 15:43
How did you try the supplied code if there is no way it compiles ? letter1 and letter2 are not really in scope. I think you want number1 and number2 — imichaelmiers
– imichaelmiers, Commented Apr 9, 2012 at 15:43
fixed the letter/number thing. Sorry about that. Alain is right, it's actually sorting an array of characters. The second column is the number of occurrences in the text file. — Sam032789
– Sam032789, Commented Apr 9, 2012 at 15:47

Paaske · Accepted Answer · 2012-04-09 17:02:21Z

2

It seems like your print method is bad (or your supplied code is not enough to reproduce your error). Your code prints the first time, but then hits an ArrayIndexOutOfBoundsException (which you should get too, if this is the actual issue).

Try this print method instead, it works for me.

public static void print(int[][] array) {
    for (int i = 0; i < array.length; i++) {
        System.out.println("[" + array[i][0] + "][" + array[i][1] + "]");
    }
}

edited Apr 9, 2012 at 17:02

answered Apr 9, 2012 at 15:56

Paaske

4,4031 gold badge24 silver badges33 bronze badges

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

2 Comments

Sam032789 Over a year ago

Ah, I was wondering if it was my print method. You see, the problem is that at the time of the array implementation, I'm not to know the amount of characters in the text. So I end up with a bunch of [0][0]'s in there too. I guess now I know the sorting works.

Paaske Over a year ago

Yes, the sorting was just fine :-)

Collectives™ on Stack Overflow

Java: Sorting a 2D array based on the second column's values

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related