> What are you doing with the list once you generate it? Are you just running > that single line of code, for instance, in a Python shell, or is this error > generated in a view?
Attempt to "cast" QuerySet to list appeared during my experimentation with Python/Django to see what I can do with both, and how practical efficient both are for me. In this particular case, I am trying to reproduce in Django one of the simplest techniques to implement "Previous"/Next" type of navigation from records. So, in this case, I open a Concept record. Instead of going back to a page with the list of "concepts" I want to go directly to the next concept that would appear next in such list. > Can you post the rest of the code around this, or at least more of a > traceback, unless that is really all that there is? And if it is, then I'd > really like to take a look at your model definition. Absolutely. I am glad you are willing to look at it - many thanks. See below. Also, I would like to mention that there is no problem to find workaround (in fact, on of them is in the code below (commented out)). But I was just surprised that I could even do such seemingly simple thing as list(QuerySet). Best, regards, Serge ===== in urls.py: ====== (r'^test/([-a-z0-9]+)/$', views.test), ===== in views.py: ======= see formatted http://dpaste.com/hold/552703/ same as: def test(request, slug=None): slugs = Concept.objects.filter(status__slug = 'active').order_by('- published_on').values_list('slug', flat=True) try: concept = Concept.objects.get(slug = slug, status__slug = 'active') except Page.DoesNotExist: raise Http404 slugs_list = list(slugs) # ======> problem line # object_slug = concept.slug # index = 1; # break_at_index = - 1; # previous_slug = None; # next_slug = None; # # for slug in slugs: # if object_slug == slug: # break_at_index = index + 1 # else: # if index == break_at_index: # next_slug = slug # break # else: # previous_slug = slug # # index += 1 concept_opportunities = Opportunity.objects.filter(opportunity_concepts = concept.concept_id, status__slug = 'active') concept_resources = concept.concept_resources.all() concept_types = concept.concept_types.all() concept_tags = concept.tags.all() context = { 'header_title':'Concept', 'object': concept, 'concept_resources': concept_resources, 'concept_types': concept_types, 'concept_opportunities': concept_opportunities, 'concept_tags': concept_tags, 'previous_slug':previous_slug, 'next_slug':next_slug, 'page_marker':'co', 'index': index - 1, } return render_to_response('page_concept.html', context, context_instance=RequestContext(request)) ===== in models.py ======== class Concept(models.Model): concept_id = models.AutoField(primary_key=True) name = models.CharField(unique=True, max_length=100) slug = models.SlugField(max_length=45, blank=True, unique=True) meta_keywords = models.CharField(null=True, blank=True, max_length=300 ) meta_description = models.CharField(null=True, blank=True, max_length=300 ) status = models.ForeignKey(Status) enable_comments = models.BooleanField() description = models.CharField(null=True, blank=True, max_length=1500, help_text='The body of concept item') published_on = models.DateField(null=True, blank=True) review_by = models.DateField(null=True, blank=True, help_text='Date when the record should be reviewed to verify if the concept still holds true.') date_created = models.DateField(auto_now_add=True, editable=False) date_updated = models.DateField(auto_now=True, editable=False) created_by = models.ForeignKey(User, null=True, blank=True, related_name="concept_created_by", editable=False) updated_by = models.ForeignKey(User, null=True, blank=True, related_name="concept_updated_by", editable=False) concept_resources = models.ManyToManyField(Resource) concept_types = models.ManyToManyField(Type) tags = TaggableManager(blank=True) class Meta: ordering = ['published_on'] verbose_name = "Concept" verbose_name_plural = "Concepts" def __unicode__(self): return self.name ===== traceback ========= http://dpaste.com/552702/ -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
