*/
public static Instances fromStringToNominal(Instances dataset, Object ...columns ){
Instances translated_dataset = dataset;
StringToNominal translator = new StringToNominal(); // new instance of filter
for(int i=0; i<columns.length; i++){
String[] options = new String[2];
options[0] = "-R"; // "range"
options[1] = columns[i].toString();
try{
translator.setOptions(options); // set options
translator.setInputFormat(translated_dataset); // inform filter about dataset **AFTER** setting options
translated_dataset = Filter.useFilter(translated_dataset, translator); // apply filter
}catch(Exception e){
System.out.println("Exception in filtering the dataset:");
e.printStackTrace();