我的defaultdict（list）不会显示在模板上，但在我看来

问题描述

我想知道为什么我的 defaultdict（list）将在我的views.py中测试时显示，但是当我去显示我的模板上的数据时，我什么都没有，甚至没有错误

任何建议？

这是我的views.py - confirm_list是我的defaultdict（list） p>

  def confirmations_report（request，* args，** kwargs）：
来自invest.models import投资，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 = {} 
 
如果request.POST：
 form = ConfirmationsForm（request.POST）
如果form.is_valid（）：
 start_date = form.cleaned_data ['start_date'] 
 end_date = form.cleaned_data ['end_date'] 
 invest = Investment.objects.all（）。 （contract_no =，maturity_date__range =（start_date，end_date））。order_by（'financial_institution'）
 for i in investment：
 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.pl a.get_primary_owner（）。member.client.sin，
'type'：i.product.code，
'purchase_amount'：i.amount，
'purchase_date'：i.start_date， 
}）
上下文['投资'] =投资
上下文['confirmlist'] = confirm_list 
为key，值在confirm_list.items（）中：
 print key 
上下文['inv'] =投资
如果request.POST.has_key（'print_report_submit'）：
上下文['show_report'] = True 
上下文[' 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（），mime type ='application / pdf'）
 response ['Content-Disposition'] ='attachment; filename = unreceived-confirmations.pdf'
 return response 
 
 else：
 form = ConfirmationsForm（）
 
上下文['form'] = form 
 return render_to_response（'reports / admin / confirm_report.html'，RequestContext（request，context））
  

但是当我这样做：

 为key，值在confirm_list.items（）中：
打印键，值
  

在我的模板如下：

  {％extends'reports / admin / base.html'％} 
 {％load humanize％} 
 
 {％block report_html％} 
< h3>未接收确认报告< / h3> 
< form method =postaction => 
< 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 =submitvalue =查看报告> 
< input type =submitname =print_report_submitvalue =打印报告/> 
< / form> 
 {key for key，value in confirmlist.items％} 
 {{key}}  -  {{value}} 
 {％endfor％} 
 {％endblock％} 
  

我什么都没有。

在views.py

  33 [{'fi_address1'：u'Scotiabank FAS'中测试时输出的输出示例， '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：＃，＃>}] 
  pre> 
 
解决方案
这是因为Django模板语言。当您尝试循环使用字典项目时，
  {％的键值，confirmlist.items％中的值
  
 Django首先为 confirmlist ['items'] 。因为这是一个 defaultdict ，返回一个空列表。
 
 
 
这是一个残酷的骗子，我已经为了解决这个问题，请将defaultdict转换成字典，然后再将其添加到模板上下文中。
 
 $ b 
 $ b 
 上下文['confirmlist'] = dict（confirm_list）
  
或者，根据sebastien trottier在他的中的解释，设置
  default_factory 至无添加到模板上下文
  confirm_list.default_factory =无
上下文['confirmlist'] = confirm_list 
  
 
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: #, #>}]
 解决方案 
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
                        
这篇关于我的defaultdict（list）不会显示在模板上，但在我看来的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！