3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = array('a' => 10, 'z' => 10, 'c' => 10, 'b' => 11, 'd' => 10); $b = array(); foreach($a as $k => $v) $b[$v][] = $k; ksort($b); $a = array(); foreach($b as $k => $v) { foreach($v as $i) $a[$i] = $k; } var_dump($a);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.38, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
array(5) { ["a"]=> int(10) ["z"]=> int(10) ["c"]=> int(10) ["d"]=> int(10) ["b"]=> int(11) }
preferences:
263.71 ms | 405 KiB | 451 Q