django - Python: Element order in dictionary

Question

Here is my Django code that does not work as expected:

posts = Post.objects.all().order_by('-added')[:20] # ordered by 'added'
post_list = dict([(obj.id, obj) for obj in posts])

# ... some operations with dictionary elements go here ...

posts_to_return = [post for post_id, post in post_list.items()] # order by 'id' now!

Is there a way to keep the original element order, so the posts would be ordered by added in posts_to_return?

Thank you!

EDIT: Python 2.6, Django 1.3

Answer 1

Dicts in python (and most languages) have no order. You should instead use collections.OrderedDict. This will retain the order of items as they are added. You can also look at the sorted() builtin if the order of addition isn't the order you're trying to preserve.