Sorting 2d String array using java

Question

I am trying to sort a string 2d array taken as user input. But this code is working for some cases and not working for some.

The code is:

 public class Source {
    public static void main(String args[]) throws Exception {
        Scanner sc = new Scanner(System.in);
        String[][] customerDetails= new String[5][3];
        customerDetails[0][0]="10";
        customerDetails[0][1]="Raj";
        customerDetails[0][2]="Chennai";
  
        customerDetails[1][0]="100";
        customerDetails[1][1]="Akshay";
        customerDetails[1][0]="Pune";

        customerDetails[2][0]="20";
        customerDetails[2][1]="Simrath";
        customerDetails[2][2]="Amristar";

        customerDetails[3][0]="30";
        customerDetails[3][1]="Gaurav";
        customerDetails[3][2]="Delhi";

        customerDetails[4][0]="101";
        customerDetails[4][1]="Ganesh";
        customerDetails[4][2]="Chennai";

    
        
        /*for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 3; j++) {
                //customerArray[i][j] = sc.nextLine();
            }
        }*/

        Arrays.sort(customerArray, (a, b)->a[0].compareTo(b[0]));
        
        for (int y = 0; y < 5; y++) {
            for (int z = 0; z < 3; z++) {
                System.out.println(customerArray[y][z]);
            }
        }
    }
}

I have given direct inputs in this code. I want to sort the numbers as String

It might be helpful to include expected output. And note: in order to provide a real minimal reproducible example to us, it would be better to "hardcode" your input data in your code here. We dont know what data you read on your machine from your input scanner! — GhostCat
– GhostCat, Commented Mar 17, 2022 at 12:45
It looks like the first input is an integer, but in your compare function you are comparing them as a string. Can you confirm that you want to sort the array based on Integer comparison? — Anton Belev
– Anton Belev, Commented Mar 17, 2022 at 12:53

UkFLSUI · Accepted Answer · 2022-03-17 13:06:23Z

2

You are getting wrong answer because you were comparing 0th index of each row of 2D array which are String. So, according to string comparison logic the outputs are correct. To get the sorting order as integer, you have to convert 0th index of each row to Integer in your comparator.

Modify your sort method call like below which should work according to your expectation because a[0] and b[0] are converted to Integer before comparison:

Arrays.sort(customerArray, (a, b)->Integer.valueOf(a[0]).compareTo(Integer.valueOf(b[0])));

Output:

10
Akhil
Pune
20
Rajni
Hyderabad
30
Praveen
Delhi
100
Rohith
Chennai
101
Sam
Bangalore

answered Mar 17, 2022 at 13:06

UkFLSUI

5,6906 gold badges38 silver badges50 bronze badges

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

Collectives™ on Stack Overflow

Sorting 2d String array using java

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