note 109493 deleted from function.usort by danbrown

Note Submitter: vos ---- Jian Wu, actually your code doesn't preserve the original order. It works for arrays with few entries, but if you try it for, say, array of 9 objects, you can see that the order is random no matter 0 or 1 you return when values are equal. I needed a way to make usort() key-preserving, and came up with the most straight-forward way: when the values are equal, we additionally compare the keys. Unfortunately, usort()'s $callback function doesn't have parameters for keys, and array_search() is slow, so I used uksort() for that. (my goal was to sort a list of strings by number of '/'es in them) <?php $urls = [ 'url://somehost/', 'url://somehost/1.htm', 'url://somehost/2_dir/', 'url://somehost/3.htm', 'url://somehost/dir_4/', 'url://somehost/dir_4/subdir/', 'url://somehost/2_dir/file.txt', ]; uksort($urls, function ($a, $b) use ($urls) { $countA = substr_count($urls[$a], '/'); $countB = substr_count($urls[$b], '/'); if ($countA != $countB) { return $countA - $countB; } else { return $a - $b; } }); print_r($urls); ?> output: Array ( [0] => url://somehost/ [1] => url://somehost/1.htm [3] => url://somehost/3.htm [2] => url://somehost/2_dir/ [4] => url://somehost/dir_4/ [6] => url://somehost/2_dir/file.txt [5] => url://somehost/dir_4/subdir/ ) (as you can spot, uksort() preserves the keys, so if you want straight 0..N keys, you can use array_values())