Online PHP editor | refs for OkDhv

<?php function sorter($array) { // find the key which doesn't have a matching value $unique = array_diff(array_keys($array), $array); $key = reset($unique); $value = $array[$key]; $result = array($key => $value); // follow the values backwards until the key matches the value while ($key != $value) { $key = $array[$key]; $value = $array[$key]; $result = array($key => $value) + $result; } return $result; } $main = array( 'lorem' => 'lorem', 'ipsum' => 'duis', 'sit' => 'adipiscing', 'duis' => 'sit', 'amet' => 'elit', 'consectetur' => 'lorem', 'adipiscing' => 'consectetur', 'eiusmod' => 'ipsum', 'labore' => 'eiusmod', 'dolore' => 'labore', 'magna' => 'dolore', 'aliqua' => 'amet', 'incididunt' => 'magna', 'tempor' => 'incididunt', 'sed' => 'tempor', 'elit' => 'sed', ); print_r(sorter($main));