public function indexOfValue($value)
    {
        $name = $this->getNameByValue($value);
        if(!is_null($name))
        {
            return $this->indexOfKey($name);
        }
        return -1;
    }
public function indexOfValue($value)
    {
        $name = $this->getNameByValue($value);
        if(!is_null($name))
        {
            return $this->indexOfKey($name);
        }
        return -1;
    }
public function indexOfValue ( $ value ) { $ name = $ this -> getNameByValue ( $ value ) ; if ( ! is_null ( $ name ) ) { return $ this -> indexOfKey ( $ name ) ; } return - 1 ; }
Index of element
-1 = element not found
@param mixed $value
@return int
Index of element - 1 = element not found