Converting csv to arff

For converting CSV (comma separated value) files into ARFF files you need the following two converters:

CSVLoader for loading the CSV file into an Instances object
ArffSaver to save the Instances as an ARFF file

In the following you'll find some example code to show you how to use the converters. The class takes 2 arguments:

the input CSV file
the output ARFF file

Example code:

import weka.core.Instances;
import weka.core.converters.ArffSaver;
import weka.core.converters.CSVLoader;

import java.io.File;

public class CSV2Arff {
  /**
   * takes 2 arguments:
   * - CSV input file
   * - ARFF output file
   */
  public static void main(String[] args) throws Exception {
    if (args.length != 2) {
      System.out.println("\nUsage: CSV2Arff <input.csv> <output.arff>\n");
      System.exit(1);
    }

    // load CSV
    CSVLoader loader = new CSVLoader();
    loader.setSource(new File(args[0]));
    Instances data = loader.getDataSet();

    // save ARFF
    ArffSaver saver = new ArffSaver();
    saver.setInstances(data);
    saver.setFile(new File(args[1]));
    saver.setDestination(new File(args[1]));
    saver.writeBatch();
  }
}

Note: with versions of Weka later than 3.5.3 the call of saver.setDestination(new File(args[1])); is no longer necessary, it is automatically done in the saver.setFile(new File(args[1])); method.

Converting csv to arff

See also#