note 109329 added to function.usort

The usort function actually moves $b up when the callback function returns both 0 and 1. If you want to preserve the original order in the array, return 1 when $a == $b instead of 0. Try this code below to see how usort alters the order of the original array when all values are the same. <?php class TestObj { private $name; private $id; function TestObj($name, $id) { $this->name = $name; $this->id = $id; } static function cmp_obj($a, $b) { $al = strtolower($a->name); $bl = strtolower($b->name); if ($al == $bl) { return 0; // return 1 if you don't want $b to go in front of $a } return ($al > $bl) ? +1 : -1; } } $a[] = new TestObj("a", 1); $a[] = new TestObj("a", 2); $a[] = new TestObj("a", 3); var_dump($a); usort($a, array("TestObj", "cmp_obj")); var_dump($a); ---- Server IP: 64.71.164.2 Probable Submitter: 198.183.141.65 ---- Manual Page -- http://www.php.net/manual/en/function.usort.php Edit -- https://master.php.net/note/edit/109329 Del: integrated -- https://master.php.net/note/delete/109329/integrated Del: useless -- https://master.php.net/note/delete/109329/useless Del: bad code -- https://master.php.net/note/delete/109329/bad+code Del: spam -- https://master.php.net/note/delete/109329/spam Del: non-english -- https://master.php.net/note/delete/109329/non-english Del: in docs -- https://master.php.net/note/delete/109329/in+docs Del: other reasons-- https://master.php.net/note/delete/109329 Reject -- https://master.php.net/note/reject/109329 Search -- https://master.php.net/manage/user-notes.php