Java String array values to 2D int array-CodePudding

I am a beginner and I have a matrix in a CSV file like this:

0;1;1;0
1;0;1;1
1;1;0;0
0;1;0;0

And I want to import it into a 2D int array so I can do multiplications with it and calculate some stuff for my graph program. This is my code so far:

try
    {
        BufferedReader br = new BufferedReader(new FileReader(path));
        String line = "";

        while ((line = br.readLine()) != null)
        {
            String[] values = line.replaceAll("\\D ","").split(";");

            for (int i = 0; i < values.length; i  )
            {
                for (int j = 0;j< values.length;j  )
                {
                    test[i][j] = Integer.parseInt(values[i]);
                    System.out.print(test[i][j]);
                }
                System.out.println();
            }
        }
        System.out.println("****");
    } catch (IOException e)
    {
        e.printStackTrace();
    }

My problem is that it will put all values from the first line into the first [] of the matrix and doesn't put every single value in each []. I tried different approaches but I always have the same outcome. I kindly ask for help.

Edit: I didn't clarify my issue properly. My code takes the first like "0110" and doesn't put each value into each place of the first line of my matrix. It should be test[0][0] has the value 0, test[0][1] has the value 1, test[0][2] has the value 1, test[0][3] has the value 0. And the same for the other lines. But it puts the whole line in [0][0] and also cuts off the first number. So it doesn't have 0110 in that place but 110.

CodePudding user response：

You need to have an increment variable that can be used to change the row for the matrix. Try the below code:

try {
BufferedReader br = new BufferedReader(new FileReader(path));
String line = "";
int rowNumber = 0;
while ((line = br.readLine()) != null) {
    String[] values = line.split(";");
    for (int j = 0; j < values.length; j  ) {
        test[rowNumber][j] = Integer.parseInt(values[j]);
        System.out.print(test[rowNumber][j]);
    }
    rowNumber  ;
    System.out.println();
}
System.out.println("****");
} catch (IOException e) {
    e.printStackTrace();
}

CodePudding user response：

Use the while loop to deal with each line. Use a variable (i below) to remember the line you're in. Then just loop over the splitted line like you alread do, but use the correct index for values (j, not i):

    BufferedReader br = new BufferedReader(new FileReader(path));
    String line = "";

    int i = 0; //to remember the line
    while ((line = br.readLine()) != null) {
        String[] values = line.replaceAll("\\D ","").split(";");
        for (int j = 0; j<values.length; j  ) {
            test[i][j] = Integer.parseInt(values[j]); //use j here, not i!
            System.out.print(test[i][j]);
        }
        i  ;
    }

CodePudding user response：

Try using just "i" as index for values, as the inner loop is not needed, you read values from csv in line-by-line manner, do something like this:

try {
    BufferedReader br = new BufferedReader(new FileReader(path));
    String line = "";
    
    int i = -1;    //here i will act as number of lines that have been "read"
    while ((line = br.readLine()) != null) {
        i =1;    //incrementing i to increase line count, and move array to next iteration
        String[] values = line.replaceAll("\\D ","").split(";");
        for (int j = 0; j < values.length; j  ) {
            test[i][j] = Integer.parseInt(values[j]);
            System.out.print(test[i][j]);
            System.out.println();
        }    //j for loop close
    }    //while close
    System.out.println("****");
} catch (IOException e) {
    e.printStackTrace();
}