Retrieve multiple products by custom attribute [magento] - magento

Question

I have a custom attribute for the products, and lets say I have 3-4 products that have the same value on that attribute. So, now I want to load these 3 products and store them in an array. Here's what I do:
$all_products = array();
$count = 0;
$collection = Mage::getModel('catalog/product')->getCollection();
$collection->addAttributeToSelect('ordernumber');
foreach($collection as $product)
{
$all_products[count] = array ('sku' => $product->getSku(), 'qty' => $this->getRequest()->get('qty'), 'size' => $product->getSize());
$count++;
}
return $all_products;
Note: ordernumber HAS a value, I just get it from another place.
Anyway, when I run it - I have no values. When I debug - the debugger terminates at $products[count] = ....
I tried loading a single product just by the custom attribute - Mage::...->loadByAttribute('ordernumber', $ordernumber); and it worked fine.
So, my guess is that I am not doing something correctly with the collection manipulation, or with the array, although, I saw some examples where I got the idea from.
What am I doing wrong?

Answer 1

Try it like this:
$all_products = array();
$count = 0;
$collection = Mage::getModel('catalog/product')->getCollection();
$collection->addAttributeToSelect('ordernumber');
//add a filter if needed - uncomment the next 2 lines and adjust the value or $ordernumber
//$ordernumber = '123';
//$addAttributeToFilter('ordernumber', $ordernumber)
foreach($collection as $product)
{
$all_products[$count] = array ('sku' => $product->getSku(), 'qty' => $this->getRequest()->get('qty'), 'size' => $product->getSize());
$count++;
}
return $all_products;