protected void copyInstances(int from,Instances dest,int num){
  for (int i=0; i < num; i++) {
    dest.add(instance(from + i));
  }
}

protected void copyInstances ( int from , Instances dest , int num ) { for ( int i = 0 ; i < num ; i ++ ) { dest . add ( instance ( from + i ) ) ; } }
copies instances from one set to the end of another one .
