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copied!<p>An array is <em>not</em> a container for linked list. <a href="http://en.wikipedia.org/wiki/Linked_list" rel="nofollow noreferrer">A linked list is a list with <em>linked</em> objects</a>, not a list with objects that have relationships. Basically, what you've got is the worst of the two containers. I would try to transform that structure into some other data container; a real linked list never needs to be sorted the way you need to sort your data.</p> <p>The good way would involve something like that. I'll leave to you the way to insert objects in the middle of the list, it's not that hard.</p> <pre><code><?php class LinkedObject { var $value; var $prev; var $next; public function __construct($value, $prev = null, $next = null) { $this->value = $value; $this->prev = $prev; $this->next = $next; } public function append(LinkedObject $insertee) { $link = $this; while($link->next != null) $link = $link->next; $link->next = $insertee; $insertee->prev = $link; } public function __toString() { $str = $this->value; if($this->next != null) { $str .= " » "; $str .= $this->next; } return $str; } } $head = new LinkedObject("foo"); $head->append(new LinkedObject("bar")); $head->append(new LinkedObject("baz")); echo $head . "\n"; // gives "foo » bar » baz" ?> </code></pre> <p>But, if for some occult reason you really, really need them in an array, here is what you would need:</p> <pre><code><?php function find_row($array, $id) { foreach($array as $current_row) { if($current_row['id'] === $id) return $current_row; } return null; } function what_the_heck_sort($array) { $start_record = $array[0]; $working_record = $array[0]; $result = array($working_record); while($working_record['prev'] !== null) { $working_record = find_row($array, $working_record['prev']); array_unshift($result, $working_record); } $working_record = $start_record; while($working_record['next'] !== null) { $working_record = find_row($array, $working_record['next']); array_push($result, $working_record); } return $result; } // the test code $test = array( array("foo 01", 'id' => 0, 'prev' => null, 'next' => 1), array("foo 02", 'id' => 1, 'prev' => 0, 'next' => 2), array("foo 03", 'id' => 2, 'prev' => 1, 'next' => 3), array("foo 04", 'id' => 3, 'prev' => 2, 'next' => 4), array("foo 05", 'id' => 4, 'prev' => 3, 'next' => 5), array("foo 06", 'id' => 5, 'prev' => 4, 'next' => 6), array("foo 07", 'id' => 6, 'prev' => 5, 'next' => 7), array("foo 08", 'id' => 7, 'prev' => 6, 'next' => 8), array("foo 09", 'id' => 8, 'prev' => 7, 'next' => 9), array("foo 10", 'id' => 9, 'prev' => 8, 'next' => null)); shuffle($test); print_r(what_the_heck_sort($test)); ?> </code></pre> <p>But really, do yourself a favor, and do a real linked list, using objects and not arrays. The sorting method above is, in my opinion, quite decent knowing the constraints, but it's <strong>ridiculously slow</strong> because it needs to look up the array for each id.</p>

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