For an object, you can access its member attributes in array mode and object mode. 100-php Tutorial

For an object, you can access its member attributes in array mode and object mode; 100 points: class {
Public $ aaa = 1;

}

$ A = new ();
Echo $ a-> aaa; // 1
At the same time, you can directly:
Echo $ a ['AAA']; // 1

In PDO, we can implement $ db-> fetch (PDO: FETCH_LAZY). This shows that PHP can achieve the above results. how can we implement it?
Thank you for your consideration;

Reply to discussion (solution)

 b = 1;$a['b'] = 2;echo $a->b;echo $a['b'];

ArrayObject can be inherited, but sub-classes are not allowed to have methods. For more information, see the manual...
I don't think it makes sense to say anything out of the box...

You need to write a method implementation.

class a{    public $aaa=1;    function fetch($type){        if($type=='assoc'){            $ret = new stdClass();            $ret->aaa = $this->aaa;        }elseif($type=='array'){            $ret = array();            $ret['aaa'] = $this->aaa;        }        return $ret;    }}$d = new a();$obj = $d->fetch('assoc');var_dump($obj);$arr = $d->fetch('array');var_dump($arr);

object(stdClass)[2]  public 'aaa' => int 1array (size=1)  'aaa' => int 1