- print_r: documentation ( source)
- array_diff: documentation ( source)
- get_object_vars: documentation ( source)
<?php
$a = (object) ['color' => 'red', 'foo' => 'bar'];
$b = (object) ['color' => 'green', 'foo' => 'bar'];
$diff = array_diff(get_object_vars($a), get_object_vars($b));
print_r($diff);