First, if you aren't running into db performance problems, I wouldn't optimize. Keep everything as simple as possible, then optimize the parts that actually demonstrate themselves to be a performance issue.
If this really is a performance issue, you could solve it like this: If you know that you need the whole list why not do this logic in the view? This should only make one db query. mylist = list(MyModel.objects.filter(type="A")|MyModel.objects.filter (type="B")) mylist_type_a = [ x for x in mylist if x.type == "A" ] mylist_type_b = [ x for x in mylist if x.type == "B" ] Then pass both mylist_type_* variables in your context. On Aug 7, 1:35 am, bweiss <[email protected]> wrote: > Is there a simple way to do the following that I'm just not seeing, or > am I looking at trying to write a custom tag? The functionality I > need is similar to {% regroup %} but not quite the same... > > My app currently has a custom admin view in which I've defined a whole > bunch of different lists, which are all objects of the same model, > filtered according to different options of a field called "Type". > (eg. type_A_list = mymodel.objects.filter(Type="A"); type_B_list = > mymodel.objects.filter(Type="B"); etc.) > > I've realised that the number of database hits this involves is > inefficient, and it would be cleaner to have a single list of objects > and try to perform the logic I need at the template level. > > What I'd like to be able to do is, for a single variable, > "object_list", define subsets of this list containing objects that > meet a certain condition. So, to filter by the field "Type", I could > define lists called "type_A_list", "type_B_list", etc, that could be > iterated through in the same way as the original list. > > The reason I need to do this is to be able to use the {% if > type_A_list %} tag in order to flag when there are NO objects of a > given type. This is why (as far as I can see) the {% regroup %} tag > won't quite work, as it only lists the groups that actually have > members. > > Output would look something like: > > Type 1: > Object 1, Object 5, Object 6 > > Type 2: > There are no objects of Type 2 > > Type 3: > Object 2, Object 4 > > Does anyone have any suggestions? > > Thanks, > Bianca --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
