Importing CSV file into 2D String array

Question

I have to read a text file into a 2d Array.

The only problem I am having, is the width of the array varies, with a maximum size of 9 columns. I don't know how many rows there will be.

Some lines will have 6 columns for example, and some will have 9.

here is a small section of my CSV file:

1908,Souths,Easts,Souths,Cumberland,Y,14,12,4000
1909,Souths,Balmain,Souths,Wests,N
1910,Newtown,Souths,Newtown,Wests,Y,4,4,14000
1911,Easts,Glebe,Glebe,Balmain,Y,11,8,20000
1912,Easts,Glebe,Easts,Wests,N
1913,Easts,Newtown,Easts,Wests,N

and here is my code so far

    import java.io.*;
import java.util.*;

public class ass2 {

    public static void main(String[] args) throws IOException {
        readData();

    }

    public static void readData() throws IOException{
        BufferedReader dataBR = new BufferedReader(new FileReader(new File("nrldata.txt")));
        String line = "";

        ArrayList<String[]> dataArr = new ArrayList<String[]>(); //An ArrayList is used because I don't know how many records are in the file.

        while ((line = dataBR.readLine()) != null) { // Read a single line from the file until there are no more lines to read

            String[] club = new String[9]; // Each club has 3 fields, so we need room for the 3 tokens.

            for (int i = 0; i < 9; i++) { // For each token in the line that we've read:
                String[] value = line.split(",", 9);                
                club[i] = value[i]; // Place the token into the 'i'th "column"
            }

            dataArr.add(club); // Add the "club" info to the list of clubs.
        }

        for (int i = 0; i < dataArr.size(); i++) {
            for (int x = 0; x < dataArr.get(i).length; x++) {
                System.out.printf("dataArr[%d][%d]: ", i, x);
                System.out.println(dataArr.get(i)[x]);
            }
        }
    }

The error I get is:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 6
at ass2.readData(ass2.java:23)
at ass2.main(ass2.java:7)

Can someone please help :'(

Thank you!

Answer 1

You can use OpenCSV for read the CSV file.

// Read all
CSVReader csvReader = new CSVReader(new FileReader(new File("nrldata.txt")));
List<String[]> list = csvReader.readAll();

// Convert to 2D array
String[][] dataArr = new String[list.size()][];
dataArr = list.toArray(dataArr);

Answer 2

The problem is with your inner loop. You are trying to access 9 elements of value regardless of how many values there are on the line. First, you should move the assignment to value to be before the inner loop. Then, you need to limit the loop iterations to the minimum of 9 and the length of value:

String[] value = line.split(",", 9);                
int n = Math.min(value.length, data.length);
for (int i = 0; i < n; i++) { // For each token in the line that we've read:
    data[i] = value[i]; // Place the token into the 'i'th "column"
}

Note that the trailing elements of data will be null.