My defaultdict(list) won't show up on template but does in my view
django, django-templates, django-views, python
Solution
This happens because of the way the Django template language does variable lookups. When you try to loop through the dictionaries items,
{% for key, value in confirmlist.items %}
Django first does a dictionary lookup for `confirmlist['items']`. As this is a `defaultdict`, an empty list is returned.
It's a cruel gotcha, that I've been stung by as well!
To work around this problem, convert your defaultdict into a dictionary before adding it to the template context.
context['confirmlist'] = dict(confirm_list)
Or, as explained by sebastien trottier in his his answer to a similar question, set `default_factory` to `None` before adding to the template context.
confirm_list.default_factory = None
context['confirmlist'] = confirm_list
Problem
Possible Duplicate: Django template can’t loop defaultdict I am wondering why my `defaultdict(list)` will show when I test it in my views.py but when I go to show the data on my template, I get nothing, not even an error. Any suggestions? Here is my views.py - confirm_list is my defaultdict(list) ``` def confirmations_report(request, *args, **kwargs): from investments.models import Investment, InvestmentManager from reports.forms import ConfirmationsForm from collections import defaultdict import ho.pisa as pisa import cStringIO as StringIO import os.path confirm_list = defaultdict(list) context = {} if request.POST: form = ConfirmationsForm(request.POST) if form.is_valid(): start_date = form.cleaned_data['start_date'] end_date = form.cleaned_data['end_date'] investments = Investment.objects.all().filter(contract_no = "",maturity_date__range=(start_date, end_date)).order_by('financial_institution') for i in investments: confirm_list[i.financial_institution.pk].append({ 'fi':i.financial_institution, 'fi_address1': i.financial_institution.address1, 'fi_address2': i.financial_institution.address2, 'fi_city': i.financial_institution.city, 'fi_prov': i.financial_institution.state_prov, 'fi_country': i.financial_institution.country, 'fi_postal': i.financial_institution.postal, 'primary_owner': i.plan.get_primary_owner().member, 'sin': i.plan.get_primary_owner().member.client.sin, 'type': i.product.code, 'purchase_amount': i.amount, 'purchase_date': i.start_date, }) context['investments'] = investments context['confirmlist'] = confirm_list for key, value in confirm_list.items(): print key, value context['inv'] = investments if request.POST.has_key('print_report_submit'): context['show_report'] = True context['mb_logo'] = os.path.join(os.path.dirname(__file__), "../../../media/images/mb_logo.jpg") html = render_to_string('reports/admin/confirm_report_print.html', RequestContext(request,context)) result = StringIO.StringIO() pdf = pisa.pisaDocument(StringIO.StringIO(html.encode("ISO-8859-1")), result) response = HttpResponse(result.getvalue(), mimetype='application/pdf') response['Content-Disposition'] = 'attachment; filename=unreceived-confirmations.pdf' return response else: form = ConfirmationsForm() context['form'] = form return render_to_response('reports/admin/confirm_report.html', RequestContext(request, context)) ``` But when I do: ``` for key, value in confirm_list.items(): print key, value ``` On my template like so: ``` {% extends 'reports/admin/base.html' %} {% load humanize %} {% block report_html %} <h3>Unreceived Confirmations Report</h3> <form method="post" action=""> <table> <tr> <td> <strong> {{ form.start_date.label }}</strong> {{ form.start_date }} <strong>{{ form.end_date.label }}</strong> {{ form.end_date }} </td> </tr> </table> <input type="submit" value="View Report"> <input type="submit" name="print_report_submit" value="Print Report"/> </form> {% for key, value in confirmlist.items %} {{ key }} - {{ value }} {% endfor %} {% endblock %} ``` I get nothing. Here is a sample of the output I get when testing in the views.py ``` 33 [{'fi_address1': u'Scotiabank FAS', 'fi_country': u'Canada', 'fi_address2': u'20 Queen Street West, Suite 2600', 'fi_city': u'TORONTO', 'fi': <FinancialInstitution: NATIONAL TRUST>, 'fi_prov': u'Ontario', 'fi_postal': u'### ###', 'purchase_amount': Decimal('30000.00'), 'purchase_date': datetime.date(2011, 6, 27), 'type': u'GIC', 'sin': u'###/###/###', 'primary_owner': <Member: #, #>}] ```