/** * TRIMNONPRINTABLE * * @param mixed $stringValue Value to check * @return string */ public static function TRIMNONPRINTABLE($stringValue = '') { $stringValue = PHPExcel_Calculation_Functions::flattenSingleValue($stringValue); if (is_bool($stringValue)) { return $stringValue ? PHPExcel_Calculation::getTRUE() : PHPExcel_Calculation::getFALSE(); } if (self::$invalidChars == null) { self::$invalidChars = range(chr(0), chr(31)); } if (is_string($stringValue) || is_numeric($stringValue)) { return str_replace(self::$invalidChars, '', trim($stringValue, "..")); } return null; }