Reverse the order of a Doctrine_Collection

Question

I'm looking for a clean way to reverse the order of a Doctrine_Collection. I know it sounds weird, so let me explain my (simple) goal: I need to display the x latest/newest record, but I have to display it in the reverse order: the oldest 1st, etc.

If it's unclear, here is an example : Lets say I have this in my table (lets call it 'example') :

id      date
1       2012-01-21
2       2012-03-19
3       2012-02-21
4       2012-03-21

So far, I've done this:

Doctrine::getTable('Example')->createQuery('d')
    ->orderBy('date DESC')
    ->limit(3);

Which returns that

id      date
4       2012-03-21
2       2012-03-19
3       2012-02-21

But I want that:

id      date
3       2012-02-21
2       2012-03-19
4       2012-03-21

---

Edit:

I've found a solution to this, using intermediate array & using array_reverse on it. But it doesn't look good :(

Here is the code I've written:

    $query = Doctrine::getTable('Example')
            ->createQuery('e')
            ->orderBy('date DESC')
            ->limit(3)
        $collection = $query->execute();

        //Here is the dirty hack:
        $itemArray = array();
        foreach ($collection as $item) {
            $itemArray[] = $item;
        }
        $itemArray = array_reverse($itemArray);
        $orderedCollection = new Doctrine_Collection($doctrineClass);
        foreach($itemArray as $item) {
            $orderedCollection->add($item);
        }
        //OrderedCollection is OK but... come on! There must be a cleaner way to do it

---

Edit 2 : answer from @Adam Kiss

        $query = Doctrine::getTable('Example')
            ->createQuery('e')
            ->orderBy('date DESC')
            ->limit(3)
        $collection = $query->execute();

        //Here is the **lovely** hack:
        $orderedCollection = new Doctrine_Collection('Example');
        for ($i=($collection->count() - 1); $i>=0;$i--) {
            $orderedCollection->add($collection->get($i));
        }

Answer 1

Without intermediate array:

for ($i = $collection->count(); $i > 0; $i--) {
    $orderedCollection->add($collection->get($i));
}

Hopefully good answer:

You could export Collection to array and reverse it

$query = Doctrine::getTable('Example')
         ->createQuery('e')
         ->orderBy('date DESC')
         ->limit(3)
$collection = $query->execute();
$collection = array_reverse($collection->toArray());

Old (wrong) answer:

Maybe you should use

Doctrine::getTable('Example')->createQuery('d')
  ->orderBy('date ASC')
  ->limit(3);

Answer 2

It seems like you either have to customize Doctrine_collection to provide something similar to array_reverse within your collection-class or use some hackish approach like the following:

$keys = array_reverse($collection->getKeys());
foreach ($keys as $key) {
    $object = $collection->get($key);
}

Answer 3

If you don't want to use any special collection functionality, just iterate over of the elements in reverse order (without any overhead) you can do it pretty easy like this:

/** @var $results Doctrine_Collection this is your result collection */
$iterator = $results->getIterator();
$item = end($iterator);

do {
  var_dump($item);
} while ($item = prev($iterator));

Answer 4

If you want an ArrayCollection object, another solution to this which expands on the answer given by @adam-kiss is to use the returned value of array_reverse to construct a new ArrayCollection object which reduces the need of a for loop.

use Doctrine\Common\Collections\ArrayCollection;

$query = Doctrine::getTable('Example')
    ->createQuery('e')
    ->orderBy('date DESC')
    ->limit(3)
;
$collection = $query->execute();
$orderedCollection = new ArrayCollection(array_reverse($collection->toArray()));

Answer 5

By the looks of it, surely just remove "DESC" from the orderby. The query returns in date descending order exactly as it's told and you want it in ascending order.

Answer 6

For Doctrine\ORM\PersistentCollection

/** @var Doctrine\ORM\PersistentCollection $posts */
$posts = $category->getPosts();
for ($i = $posts->count()-1; $i >= 0; $i--) {
    $post = $posts->offsetGet($i);
    // ... do some logic
}

Answer 7

it worked for me. doctrine version: 1.2

    $collection = //make doctrine collection;
    $reversed_array = array_reverse($collection->toArray());
    $collection->fromArray($reversed_array);

Answer 8

use Doctrine\Common\Collections\Criteria;
...

$criteria = Criteria::create();
$criteria->orderBy(['id' => 'DESC']);

return $this->objections->matching($criteria);

Answer 9

maybe you should use like this

     ->orderBy('date', 'DESC')

because in this documentation http://docs.doctrine-project.org/projects/doctrine-orm/en/2.0.x/reference/query-builder.html orderby's signature requires ASC/DESC as second parameter

      public function orderBy($sort = null, $order = null);