django for loop counter break

Question

This is hopefully a quick/easy one. I know a way to work around this via a custom template tag, but I was curious if there were other methods I was over looking. I’ve created a gallery function of sorts for my blog, and I have a gallery list page that paginates all my galleries. Now, I don’t want to show all the photos of each gallery in that list, since if each gallery even has 20 images, then that’s 100 images on a page if I paginate at 5 posts. That’d be wasteful, and the wrong way to go about things.

The question I have is, is there a way to just display 3 photos from the photo set? What I’d like to do, but I don’t think is possible is something like (pseudocode):

{% for photos in gallery.photo_set %}
   {% if forloop.counter lt 3 %}
     <img src="{{ photos.url }}">
   {% endif %}
{% endfor %}

Judging from the documentation, unless I’m completely missing it, that’s not possible via the templating system. Hence, I can just write my own template tag of sorts to work around it. I could probably do something from the view aspect, but I haven’t looked to far into that idea. The other option I have is giving the model a preview field, and allow the user to select the photos they want in the preview field.

Anyways, a few different options, so I thought I’d poll the audience to see how you’d do it. Any opinion is appreciated. Personally, enjoying that there’s numerous ways to skin this cat.

Asked By: f4nt

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Source

Answer 1

Use:

{% for photos in gallery.photo_set|slice:":3" %}

Answered By: Alex Martelli

Answer 2

This is better done in the gallery.photo_set collection. The hard-coded “3” in the template is a bad idea in the long run.

class Gallery( object ):
   def photo_subset( self ):
       return Photo.objects.filter( gallery_id = self.id )[:3]

In your view function, you can do things like pick 3 random photos, or the 3 most recent photos.

   def photo_recent( self ):
       return Photo.objects.filter( gallery_id = self.id ).orderby( someDate )[:3]

   def photo_random( self ):
       pix = Photo.objects.filter( gallery_id = self.id ).all()
       random.shuffle(pix)
       return pix[:3]

Answered By: S.Lott

django for loop counter break

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