public function numericKeys()
    {
        $keys = new static;

        foreach ($this->items as $key => $value)
        {
            if (is_numeric($key)) $keys->set($key, $value);
        }

        return $keys;
    }
public function numericKeys()
    {
        $keys = new static;

        foreach ($this->items as $key => $value)
        {
            if (is_numeric($key)) $keys->set($key, $value);
        }

        return $keys;
    }
public function numericKeys ( ) { $ keys = new static ; foreach ( $ this -> items as $ key => $ value ) { if ( is_numeric ( $ key ) ) $ keys -> set ( $ key , $ value ) ; } return $ keys ; }
Return items only with numeric keys.

@return static
Return items only with numeric keys .