CSV not showing correct data

Question

    package aplikacja;
    import java.io.*;

    public class Plik {
        double wymiary[] =  {10, 23, 4};

        public void zapisz_dane() throws IOException{
           RandomAccessFile raf = new RandomAccessFile("pomiary.csv", "rw");
            for(int i =0; i<wymiary.length; i++){
                raf.writeDouble(wymiary[i]);
            }
            raf.close();
        }

    }

And this:

    package aplikacja;
    import java.io.*;
    import aplikacja.*;

    public class Main {
        public static void main (String []args) throws IOException {
            Plik plik = new Plik();
            plik.zapisz_dane();
        }
    }

When I open CSV files I have chars insides CSV file:

@$@7@

But I would like to have 10, 23 and 4. How to fix it?

It is working for String but not for double or int. Do you know why?

Check out the javadoc on RandomAccessFile.writeDouble(double). You are writing out a byte representation of the double values, not String representation. You may want to use a PrintWriter to write to your underlying File. And don't forget to write the commas - its only comma-separated if you separate things with commas! — vsfDawg, May 06 '20 at 17:29

score 0 · Answer 1 · answered May 07 '20 at 00:15

A solution using PrintWriter:

package aplikacja;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;

public class Plik {

  double[] wymiary = { 10, 23, 4 };

  public void zapiszDane() throws IOException {

    File file = new File("pomiary.csv");

    try (PrintWriter pw = new PrintWriter(file)) {
      for (int i = 0; i < wymiary.length; i++) {
        pw.println(wymiary[i]);
      }
    }

  }
}

pomiary.csv result:

10.0
23.0
4.0

Note: in general there is no way to determine the decimal precision of a double value. If you want decimal precision in Java, you could use BigDecimal.

score -1 · Answer 2 · answered May 06 '20 at 17:22

-1

You need to specify the charset (usually UTF-8). See here for how to do it. There are more information on that stack overflow thread.

answered May 06 '20 at 17:22

fpezzini

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CSV not showing correct data

2 Answers2