how to write to a new line of CSV file

Question

I am trying to benchmark sorting methods. My writeCSV(String) method writes over the first line every time I call it. Here is my code:

public static void main(String[] args) throws Exception{

    writeCSV("data size (100 times),bubble,insertion,merge,quick");

    sortRandomSet(20);
}

 public static void sortRandomSet(int setSize) throws Exception
{
    .
    .
    .
    writeCSV(setSize+","+bTime+","+mTime+","+iTime+","+qTime);
}
/*******************************************************************************
* writeCSV(course[]) method
* Last edited by Steve Pesce 3/19/2014 for CSci 112
* Writes String to CSV
* 
*/
public static void writeCSV(String line) throws Exception {

    //create new File object 
    java.io.File courseCSV = new java.io.File("benchmark.csv");

    //create PrintWriter object on new File object
    java.io.PrintWriter outfile = new java.io.PrintWriter(courseCSV);

    outfile.write(line + "\n");

    outfile.close();
}//end writeCSV(String)

I want writeCSV to start on a new line every time it is called, is this possible to do?

I will use the append method because I have used it before; The random access file seemed like a fine solution too. — user2809114, Mar 31 '14 at 03:16
If any of the answers helped to resolve the issue, please remember to mark it as accepted. — shree.pat18, Mar 31 '14 at 03:24

score 1 · Answer 1 · edited May 23 '17 at 12:22

1

Yeah, right after your call function you can add a string to the first line, have you tried that?

Also, when you create a new file add "a" as an argument which stands for append.

Try using RandomAccessFile

Have a look at this, it should explain how to add things to selected line in a text file

edited May 23 '17 at 12:22

Community

1
1

answered Mar 31 '14 at 03:04

MrHaze

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When you write to a file, add a line of code that write to the first line, have a look at the link i added, it should explain how – MrHaze Mar 31 '14 at 03:09

score 1 · Answer 2 · answered Mar 31 '14 at 03:08

1

Use java.io.FileWriter instead:

java.io.FileWriter outfile = new java.io.FileWriter("benchmark.csv", true); //true = append
outfile.write(line+"\n");

answered Mar 31 '14 at 03:08

AndrewWhalan

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score 1 · Accepted Answer · answered Mar 31 '14 at 03:09

1

You could just use the append method. This will append your input to the end of the file.

answered Mar 31 '14 at 03:09

shree.pat18

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He wants to write over the first line. – MrHaze Mar 31 '14 at 03:09
2

No he doesn't. The last line says "I want writeCSV to start on a new line every time it is called" – shree.pat18 Mar 31 '14 at 03:10

score 0 · Answer 4 · answered Aug 10 '16 at 08:18

0

You should use "append method for this"

answered Aug 10 '16 at 08:18

Yogesh Nikam Patil

1,192
13
18

1

it should be a comment. – Inzimam Tariq IT Aug 10 '16 at 08:37

how to write to a new line of CSV file

4 Answers4