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获取Django表单时出现“值过多无法解包”

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2 回答
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提问于 2025-04-18 09:41

我正在尝试从一个表单中获取一些数据，并根据这些数据过滤结果。如果我用一种比较乱的方式（直接从请求中获取数据），是可以工作的，但用Django的正规方式（注释掉的部分）就不行。我总是遇到“解包的值太多”的异常。可能是什么问题呢？

if request.method == 'POST':
    print request.POST
    entries = entries.filter(date__year=request.POST['year'])
    #spanform = SpanForm(request.POST)
    #print spanform
    #if spanform.is_valid():
    #   cd = spanform.cleaned_data
    #   if cd['year']:
    #       entries = entries.filter(date__year=cd['year'])

这是表单的代码：

class SpanForm(forms.Form):

    year = forms.ChoiceField(label="")

    def __init__(self, years, *args, **kwargs):
        super(SpanForm, self ).__init__(*args, **kwargs)
        if years:
            self.fields['year'].choices = years

所以，当我测试以下这段代码时：

if request.method == 'POST':
    #print request.POST
    #entries = entries.filter(date__year=request.POST['year'])
    spanform = SpanForm(request.POST)

    if spanform.is_valid():
       cd = spanform.cleaned_data
       if cd['year']:
           entries = entries.filter(date__year=cd['year'])

我得到了以下的错误信息：

Environment:


Request Method: POST
Request URL: http://localhost:5000/entries/

Django Version: 1.6.2
Python Version: 2.7.5
Installed Applications:
('django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'core')
Installed Middleware:
('django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware')


Template error:
In template /Users/wswld/Code/calc/core/templates/entries.html, error at line 9
   too many values to unpack
   1 : {% extends "dashboard.html" %}


   2 : {% load staticfiles %}


   3 : 


   4 : {% block tab %}


   5 : 


   6 : <form action="." method="post">


   7 : {% csrf_token %}


   8 :         <table>


   9 :              {{form.as_p}} 


   10 :         </table>


   11 :         <input type="submit" value="Apply" />


   12 : </form>


   13 : 


   14 : <table>


   15 : {% for entry in data %}


   16 : <tr>


   17 :     <td>


   18 :         <a href="./{{ entry.uuid }}/">


   19 :             <img src="{% static "permalink.png" %}"  height="15" width="15"></img>


Traceback:
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/core/handlers/base.py" in get_response
  114.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/contrib/auth/decorators.py" in _wrapped_view
  22.                 return view_func(request, *args, **kwargs)
File "/Users/wswld/Code/calc/core/views.py" in dashboard
  82.     return render(request, '%s.html' % tab, {'tab': tab, 'data': data, 'form': spanform})
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/shortcuts/__init__.py" in render
  53.     return HttpResponse(loader.render_to_string(*args, **kwargs),
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/loader.py" in render_to_string
  169.         return t.render(context_instance)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in render
  140.             return self._render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in _render
  134.         return self.nodelist.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in render
  840.                 bit = self.render_node(node, context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/debug.py" in render_node
  78.             return node.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/loader_tags.py" in render
  123.         return compiled_parent._render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in _render
  134.         return self.nodelist.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in render
  840.                 bit = self.render_node(node, context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/debug.py" in render_node
  78.             return node.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/loader_tags.py" in render
  123.         return compiled_parent._render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in _render
  134.         return self.nodelist.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in render
  840.                 bit = self.render_node(node, context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/debug.py" in render_node
  78.             return node.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/loader_tags.py" in render
  62.             result = block.nodelist.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in render
  840.                 bit = self.render_node(node, context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/debug.py" in render_node
  78.             return node.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/loader_tags.py" in render
  62.             result = block.nodelist.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in render
  840.                 bit = self.render_node(node, context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/debug.py" in render_node
  78.             return node.render(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/debug.py" in render
  88.             output = self.filter_expression.resolve(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in resolve
  585.                 obj = self.var.resolve(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in resolve
  735.             value = self._resolve_lookup(context)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/template/base.py" in _resolve_lookup
  789.                             current = current()
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/forms/forms.py" in as_p
  241.             errors_on_separate_row = True)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/forms/forms.py" in _html_output
  186.                     'field': six.text_type(bf),
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/forms/forms.py" in __str__
  425.         return self.as_widget()
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/forms/forms.py" in as_widget
  475.         return widget.render(name, self.value(), attrs=attrs)
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/forms/widgets.py" in render
  504.         options = self.render_options(choices, [value])
File "/Library/Python/2.7/site-packages/Django-1.6.2-py2.7.egg/django/forms/widgets.py" in render_options
  528.         for option_value, option_label in chain(self.choices, choices):

Exception Type: ValueError at /entries/
Exception Value: too many values to unpack
django 异常处理 表单处理 数据过滤 解包错误 请求数据

2 个回答

1

在编程中，有时候我们会遇到一些问题，特别是在使用某些工具或者库的时候。这些问题可能会让我们感到困惑，不知道该怎么解决。比如，有人可能在使用某个函数时，发现它的表现和预期不一样，这时候就需要去查找原因。

通常，我们可以通过查看文档、搜索网上的资料或者在社区里提问来找到解决方案。很多时候，其他人也遇到过类似的问题，他们的经验和解决方法可以帮助我们更快地找到答案。

总之，遇到问题时不要着急，先冷静下来，尝试去理解问题的本质，再寻找解决办法。这样才能更有效地学习和进步。

class SpanForm(forms.Form):

    year = forms.ChoiceField(label="")

    def __init__(self, years, *args, **kwargs): # here you have 'years' parameter.
        super(SpanForm, self ).__init__(*args, **kwargs) 
        if years:
            self.fields['year'].choices = years

if request.method == 'POST':
    spanform = SpanForm(request.POST) # where is your 'years' parameter? Now you have request.POST in 'years' variable from __init__ from SpanForm class.

    if spanform.is_valid():
       cd = spanform.cleaned_data
       if cd['year']:
           entries = entries.filter(date__year=cd['year'])
回答于 2025-04-18 由 Python大师
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4

问题在于你没有在视图中的后置条件里传递年份这个参数。你现在是把请求中的POST字典里的年份参数传过去。你可以选择从表单中的kwargs里取出年份参数，或者在视图里传递None。

class SpanForm(forms.Form):

    year = forms.ChoiceField(label="")

    def __init__(self, *args, **kwargs):
        years = kwargs.pop('years', None)
        super(SpanForm, self ).__init__(*args, **kwargs)
        if years:
            self.fields['year'].choices = years

或者

if request.method == 'POST':
    spanform = SpanForm(None, request.POST)

    if spanform.is_valid():
       cd = spanform.cleaned_data
       if cd['year']:
           entries = entries.filter(date__year=cd['year'])
回答于 2025-04-18 由 Python大师
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