public Column removeColumn(String field){
  int idx=m_names.indexOf(field);
  if (idx < 0) {
    throw new IllegalArgumentException("No such column.");
  }
  return removeColumn(idx);
}

public Column removeColumn ( String field ) { int idx = m_names . indexOf ( field ) ; if ( idx < 0 ) { throw new IllegalArgumentException ( "No such column." ) ; } return removeColumn ( idx ) ; }
remove a data field from this table
