How to write only the 5th value from a list into a csv

Question

I am reading several csv sheet with the opencsv libary. I am storing the "read" csv file in hugeList = reader.readAll(); Now I only want to only write the 5th value of this huge csv sheet columnwise in another sheet.

At the moment I am standing at:

        //reading all entries in a huge list
        //-740 as it would take to much time to run it in "dev mode"
        for (int j = 0; j < (fileList.size() - 740); j++) { 
            String csvFile = "C:\\Users\\" + fileList.get(j);
            reader = new CSVReader(new FileReader(csvFile), ';');
            hugeList = reader.readAll();            

            List<String[]> data = new ArrayList<String[]>();
//          for(int m = 0; m < hugeList.size(); m++) {
//              String[] value = hugeList.get(m);
                data.add(hugeList.get(5));
//          }

            writer.writeAll(data);

        }

However I have no idea how to write them into another column and just take the 5th value?

I really appreciate your answer!

UPDATE 1

Goal: I have saved all values from one sheet at the time in hugeList. Now I want to write only the 5th column into a new sheet.

Problem: The logic behind this goal.

UPDATE 2

enter image description here

This is what my code looks like right now:

//reading all entries in a huge list
for (int j = 0; j < (fileList.size() - 740); j++) { 
    String csvFile = "C:\\" + fileList.get(j);
    reader = new CSVReader(new FileReader(csvFile), ';');
    hugeList = reader.readAll();            

    List<String[]> data = new ArrayList<String[]>();
    List<String> tmp= new ArrayList<String>();
     for(int m = 0; m < hugeList.size(); m++) {
              String[] values = hugeList.get(m);
              tmp.add(values[0]);       
       }
     data.add(tmp.toArray(new String[0]));


    writer.writeAll(data);

}

As you can see I get my data still vertically... Why?

Try to explain your code in [SSCCE format](http://sscce.org/). — Not a bug, Jan 07 '14 at 13:00
Why are you iterating over the inner array? Isn't `hugeList` just an array of `String` arrays or something? The inner array should be the csv lines, broken into fields, so you should be able to simply do `writer.write(hugeList[i][5])`. I think you are over-complicating things by trying to make a `List`. — CodeChimp, Jan 07 '14 at 13:02
As I understand the question: The OP is getting the list of values from the csv sheet from `fileList` in `hugeList`. Then ,I think, he wants to give out only the 5th value of each sheet in a column. Is thi correct user2051347? — Carol.Kar, Jan 07 '14 at 13:05

Festus Tamakloe · Accepted Answer · 2014-01-07T17:55:54.940

2

I thing you are already on the right way.

You have 2 possibilities.

1. data.add(hugeList.get(4));

2. for(int m = 0; m < hugeList.size(); m++) {
         if(m==4){
              String[] values = hugeList.get(m);
              data.add(values);
          break;
         }
    }

UPDATE
Goal: I have saved all values from one sheet at the time in hugeList. Now I want to write only the 5th column into a new sheet. Problem: The logic behind this goal.

enter image description here My Approach for a result in rows

List<String[]> data = new ArrayList<String[]>();
        List<String> tmp= new ArrayList<String>();
         for(int m = 0; m < hugeList.size(); m++) {
                  String[] values = hugeList.get(m);
                  tmp.add(values[4]);       
           }
         data.add(tmp.toArray(new String[0]));
        }

My Approach for a result in Column

 for (int j = 0; j < fileList.size(); j++) {
    String csvFile = readPath + fileList.get(j);
    System.out.println("Read:  " + csvFile);
    reader = new CSVReader(new FileReader(csvFile), ';');
    hugeList = reader.readAll();

    String[] data = new String[1];
    for (int m = 0; m < hugeList.size(); m++) {
        String[] values = hugeList.get(m);
        data[0] = values[0];
        writer.writeNext(data);
    }
}

edited Jan 07 '14 at 17:55

answered Jan 07 '14 at 13:01

Festus Tamakloe

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Thx for your answer! I am still getting the data verticaly not horizontally... I would appreciate it if you could have a look at my update! – user2051347 Jan 07 '14 at 16:17
1

@user2051347 May be you can send me your code if you don't have nothing against it? and a little example with excel about what you want exactly to achieve? festus@tamakloe.de – Festus Tamakloe Jan 07 '14 at 16:24
1

@user2051347. Ok i get the email with 2 attchments. I'll work on it and send it back to you today – Festus Tamakloe Jan 07 '14 at 16:37
1

@user2051347 what is the meaning of this line " for (int j = 0; j < (fileList.size() - 740); j++) { " – Festus Tamakloe Jan 07 '14 at 17:12
I have over 1000 files therefore I just limit the read files by substracting -740 from the `fileList.size()`. In fact this is just for `development mode`. – user2051347 Jan 07 '14 at 17:25
1

@user2051347 i send you a mail – Festus Tamakloe Jan 07 '14 at 17:52
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/44730/discussion-between-user2051347-and-festus-tamakloe) – user2051347 Jan 07 '14 at 18:12

How to write only the 5th value from a list into a csv

1 Answers1