public static function getColumnMap($key=NULL)
    {
        if ($key) {
            return isset(self::$_keyColumnMap[$key]) ? self::$_keyColumnMap[$key] : NULL;
        } else {
            return self::$_keyColumnMap;
        }
    }
public static function getColumnMap($key=NULL)
    {
        if ($key) {
            return isset(self::$_keyColumnMap[$key]) ? self::$_keyColumnMap[$key] : NULL;
        } else {
            return self::$_keyColumnMap;
        }
    }
public static function getColumnMap ( $ key = NULL ) { if ( $ key ) { return isset ( self :: $ _keyColumnMap [ $ key ] ) ? self :: $ _keyColumnMap [ $ key ] : NULL ; } else { return self :: $ _keyColumnMap ; } }
Get Column Alpha Map by key or all from the actived sheet

@param string|int $key Key set by addRow()
@return string|array Column alpha string | Key-Coordinate array
Get Column Alpha Map by key or all from the actived sheet