PHP Object-Oriented _ Object traversal ____php

The traversal of an object, like the traversal of a group, refers to the traversal of an instance property .
　　
The properties that are traversed below are "accessible properties" in the scope (to consider access rights).

<?php
class a{public
    $p 1 = 1;
    Protected $p 2 = 2;
    Private $p 3 = 3;
    Static $p 4 = 4;
}

$obj 1 = new A ();
foreach ($obj 1 as $key => $value) {//$key represents the properties of the object, $value its corresponding value,
    echo "<br/> Property $key:". $value   
;
>

Run Result:

It is visible that only the properties of the public adornment can be traversed, that is, how to make all the properties of an object traverse. Write a traversal method inside the class.

<?php
class a{public
    $p 1 = 1;
    Protected $p 2 = 2;
    Private $p 3 = 3;
    Static $p 4 = 4;    static property

    function Showallproperties () {
        foreach ($this as $key => $value) {
            echo <br/> Property $key: $ Value ';  
        }

}} $obj 1 = new A ();
$obj 1->showallproperties ();
? >

Run Result:

Property P1:1
Property P2:2

However, static properties are not part of the object, so they cannot be traversed.