<?php
$x = new stdclass;
$x->{42} = "foo";
$x->{"42"} = 1337;
var_dump($x);
$y = (array)$x;
var_dump($y);
$y["42"] = "wat";
var_dump($y);
$z = (object)$y;
var_dump($z);
var_dump($z->{42})
?>

object(stdClass)#1 (1) {
  ["42"]=>
  int(1337)
}
array(1) {
  ["42"]=>
  int(1337)
}
array(2) {
  ["42"]=>
  int(1337)
  [42]=>
  string(3) "wat"
}
object(stdClass)#2 (2) {
  ["42"]=>
  int(1337)
  [42]=>
  string(3) "wat"
}
int(1337)