CODEWITHSUNDEEP
phparraysobject
bobbyh
bobbyh

Reputation: 643

Sorting an Array of Objects in PHP In a Specific Order

I have two arrays in PHP. The first array ($author_array) is comprised of user_ids in a particular order, like so: (8, 1, 6)

The second array ($user_results) is comprised of an array of objects like so:

Array
(
    [0] => stdClass Object
        (
            [ID] => 1
            [user_login] => user1
        )
    [1] => stdClass Object
        (
            [ID] => 6
            [user_login] => user6
        )
    [2] => stdClass Object
        (
            [ID] => 8
            [user_login] => user8
        )
)

I'd like to "sort" the second array so it's in this order, which matches the order of the values in the first array of (8, 1, 6). So it'd look like this:

Array
(
    [0] => stdClass Object
        (
            [ID] => 8
            [user_login] => user8
        )
    [1] => stdClass Object
        (
            [ID] => 1
            [user_login] => user1
        )
    [2] => stdClass Object
        (
            [ID] => 6
            [user_login] => user6
        )
)

I'm weak on data structures. How could I do this? :-)

Thanks in advance for your help!

-Bob

Upvotes: 15

Views: 17524

Answers (4)

morecer
morecer

Reputation: 1

public static function reorganizeBykey ($objects, array $keys){
    $results = array();
    foreach($keys as $key){
        $i=0;
        foreach($objects as $object){
            if($object->sourceName==$key){
                $results[$i] = $object;
            }
            $i++;
        }
    }
    $others = (array_diff_assoc($objects,$results));
    $results = array_merge($results,$others);
    return $results;
}

I hope this is helpful – I had to use this to sort an array() by some keys() and then append what doesn't match at the end.

Upvotes: 0

David
David

Reputation: 5589

So I had a similar issue, but I was trying to order an object by an array (that wasn't an object). It's just not possible, so here's my workaround:

$sort_array= array(11, 4, 16, 19, 23);
$myobject = sort_categories($myobject)

function cmp($a, $b) { 
    if ($a->sort_key == $b->sort_key) { return 0; }
    return ($a->sort_key < $b->sort_key) ? -1 : 1;
}
function sort_categories($obj) {
    global $sort_array;

    foreach($obj as $cat) {
        $cat->sort_key = 999;
        for ($i=0;$i<count($sort_array);$i++) {
            if ($sort_array[$i] == $cat->term_id) $cat->sort_key = $i;
        }
    }
    usort($obj,'cmp');
    return $obj;
}

I'm looking through the object and adding a new (property?) called "sort_key" which we'll then use to sort on with usort() and cmp(). By default, the new sort_key will be 999 so it gets stuck at the end.

Upvotes: 1

Paul Dixon
Paul Dixon

Reputation: 300845

Use usort and provide a custom comparison function which uses the position of the key in your "ordering" array to determine the sort order, e.g. something like:

function cmp($a, $b) 
{
   global $author_array;

   $pos1=array_search ($a->ID, $author_array);
   $pos2=array_search ($b->ID, $author_array);

   if ($pos1==$pos2)
       return 0;
   else
      return ($pos1 < $pos2 ? -1 : 1);

}


usort($user_results, "cmp");

Upvotes: 30

Tom Haigh
Tom Haigh

Reputation: 57815

I'm not sure whether this will be significantly slower than other examples, but it seems simpler. It may be that you could build the $user_results array as an associative one to start with, using ID as the key, then you can easily do lookups.

$hash = array();
$result = array();

foreach ($user_results as $obj) {
    $hash[$obj->ID] = $obj;
}

foreach ($author_array as $id) {
    $result[] = $hash[$id];
}

Upvotes: 3

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