Java - Store data from file into Arrays

Question

I have got my program to read the file and even show the file info but I need to know how to store the data on the file into a two dimensional array and a one dimensional array.

The file that is read looks something like this: 1000,Adams,Olivi,80,78,61,91,20,18,18,20,19,20,19,20,20,19,20,BUS,3.1 1001,Smith,Kimberly,70,68,53,72,20,20,18,20,18,18,20,19,20,19,18,IMD,3.5 1002,Fenandez,Aaron,76,67,72,99,18,20,20,19,19,19,19,19,19,19,20,BIO,2.7

The two dimensional array has to hold all the numbers between the names and the three letters.

The one dimensional array has to hold the GPA at the end.

My question once again is: How would I get the file to store the information into the arrays?

import java.io.*;


public class StudentGrades
{
    public static void main(String[] args)
    {

        int[][] studentScores = new int[93][15];

        float[] studentGPA = new float[93];

        String fileName = "Students.txt";


        try {
            FileReader fileReader = new FileReader(fileName);
            BufferedReader bufferedReader = new BufferedReader(fileReader);

            String line;

            while((line = bufferedReader.readLine()) != null)
                System.out.println(line);
                }
            catch(IOException ex){
            System.out.println("error");
        }

    }
}

Answer 1

If you are sure that your input from the file will be always in the same form (i.e. with the same amount of data per line, and with this sequence):

public static void main(String[] args) {

        int[][] studentScores = new int[93][15];

        float[] studentGPA = new float[93];

        String fileName = "Students.txt";

        try {
            FileReader fileReader = new FileReader(fileName);
            BufferedReader bufferedReader = new BufferedReader(fileReader);

            String line;

            int studentIndex = 0;
            String[] lineSplit;
            while ((line = bufferedReader.readLine()) != null) {
                System.out.println(line);
                lineSplit = line.split(",");
                for (int k = 0; k < 15; k++) {
                    studentScores[studentIndex][k] = Integer.parseInt(lineSplit[3 + k]);
                }
                studentGPA[studentIndex] = Float.parseFloat(lineSplit[lineSplit.length - 1]);
                studentIndex++;
            }
        } catch (IOException ex) {
            System.out.println("error");
        }

    }

Answer 2

If the data in the file can have different lenght, best way to do it would be to use regex to get these data. (http://regexpal.com/ + http://www.vogella.com/tutorials/JavaRegularExpressions/article.html)

If, however, You only need a simple split etc, just split method on each line - then you will have an array with all the split values. (How to split a String in Java)

Answer 3

Initialise a variable count to zero and increment it each time you read a line from the file. That can be your index into the arrays.

Use the String.split method to split each line using the comma character. Then, using loops, insert this data into the correct array, for example:

String[] parts = input.split(",");
for (int i = 0; i < 15; i++) {
  studentScores[count][i] = parts[i+3];
}

Answer 4

Here is a full (quick-and-dirty) working example, simulating the file content by a StringRerader:

private static final String FILE_CONTENT =
        "1000,Adams,Olivi,80,78,61,91,20,18,18,20,19,20,19,20,20,19,20,BUS,3.1\n" +
        "1001,Smith,Kimberly,70,68,53,72,20,20,18,20,18,18,20,19,20,19,18,IMD,3.5\n" +
        "1002,Fenandez,Aaron,76,67,72,99,18,20,20,19,19,19,19,19,19,19,20,BIO,2.7";

public static void main(String[] args) throws IOException {
    int[][] studentScores = new int[3][15];
    float[] studentGPA = new float[3];
    BufferedReader bufferedReader = new BufferedReader(new StringReader(FILE_CONTENT));
    int count = 0;
    for (String line = bufferedReader.readLine(); line != null; line = bufferedReader.readLine()) {
        String[] values = line.split(",");
        for (int idx = 0; idx < 15; idx++) studentScores[count][idx] = Integer.parseInt(values[idx + 3]);
        studentGPA[count] = Float.parseFloat(values[19]);
        System.out.println(studentGPA[count] + " : " + Arrays.toString(studentScores[count]));
        count++;
    }
}

OUTPUT:

3.1 : [80, 78, 61, 91, 20, 18, 18, 20, 19, 20, 19, 20, 20, 19, 20]
3.5 : [70, 68, 53, 72, 20, 20, 18, 20, 18, 18, 20, 19, 20, 19, 18]
2.7 : [76, 67, 72, 99, 18, 20, 20, 19, 19, 19, 19, 19, 19, 19, 20]