How to extend the ArrayObject and create a custom array

array_object_extend.php

<?php
class MyArray extends ArrayObject {
  function __construct($array = array()){ 
    parent::__construct($array, ArrayObject::ARRAY_AS_PROPS);
  }

  public function get_property_string($sep = ':') {
    return implode($sep, $this->getArrayCopy());
  }

  public function __ToString() {
    return 'Array';
  }
}

$a = new MyArray;
$a->append('LOGIN');
$a->append('BETA_ACCESS');
$a->append('COMMENT_WRITE');

var_dump($a->get_property_string());

/*
 * Output:
 *   string(31) "LOGIN:BETA_ACCESS:COMMENT_WRITE"
 */