<?php

$x = new stdclass();
$x->{"42"} = 'foo';
$x = (array)$x;
var_dump($x);
$x[42] = 'bar';
var_dump($x); #lolwat

echo $x["42"];
echo $x[42];

array(1) {
  ["42"]=>
  string(3) "foo"
}
array(2) {
  ["42"]=>
  string(3) "foo"
  [42]=>
  string(3) "bar"
}
barbar