public static int count(Iterator tuples,String field){
  int i=0;
  for (; tuples.hasNext(); ++i, tuples.next())   ;
  return i;
}

public static int count ( Iterator tuples , String field ) { int i = 0 ; for ( ; tuples . hasNext ( ) ; ++ i , tuples . next ( ) ) ; return i ; }
get the number of values in a data column . duplicates will be counted .
