two php arrays - sort one array with the value order of another

This should be quite easy using usort, which sorts the array using a user-defined comparison function. The result might look something like this:

usort($posts, function($a, $b) use ($post_ids) {    return array_search($a->ID, $post_ids) - array_search($b->ID, $post_ids);});

Note that this solution, since it uses anonymous functions and closures, requires PHP 5.3.

One easy solution for this pre-5.3 (the dark ages!) is to do this with a quick loop and then ksort:

$ret = array();$post_ids = array_flip($post_ids);foreach ($posts as $post) {    $ret[$post_ids[$post->ID]] = $post;}ksort($ret);

You could create a nested looping mechanism to match up the order and ids and rebuild a new post array.

$new_post_array = array();foreach($id_array as $id) {          //loop through custom ordered ids    foreach($post_array as $post) {  //for every id loop through posts        if($id == $post->ID){         //and when the custom ordered id matches the post->ID            new_array[] = $post       //push the post on the new array        }    }}

$sortOrderMap = array_flip($postIds);usort($posts, function($postA, $postB) use ($sortOrderMap) {    return $sortOrderMap[$postA->ID] - $sortOrderMap[$postB->ID];});

You can simply subtract b from a instead of a from b to sort the other direction