错误：“字典更新序列元素＃0的长度为1；在Django 1.4上需要2

  • Z时代
  • 2024-01-10
  • 分类：问答

我在django 1.4上收到一条错误消息：

字典更新序列元素＃0的长度为1；2个为必填项

[编辑]

当我尝试使用模板标签时发生了这种情况：`{％for v in values％}：

dictionary update sequence element #0 has length 1; 2 is required
Request Method:     GET
Request URL:    ...
Django Version:     1.4.5
Exception Type:     ValueError
Exception Value:    
dictionary update sequence element #0 has length 1; 2 is required
Exception Location:     /usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py in __init__, line 21
Python Executable:  /usr/bin/uwsgi-core
Python Version:     2.7.3
Python Path:    
['/var/www/',
 '.',
 '',
 '/usr/lib/python2.7',
 '/usr/lib/python2.7/plat-linux2',
 '/usr/lib/python2.7/lib-tk',
 '/usr/lib/python2.7/lib-old',
 '/usr/lib/python2.7/lib-dynload',
 '/usr/local/lib/python2.7/dist-packages',
 '/usr/lib/python2.7/dist-packages',
 '/usr/lib/python2.7/dist-packages/PIL',
 '/usr/lib/pymodules/python2.7']
Server time:    sam, 13 Jul 2013 16:15:45 +0200
Error during template rendering
In template /var/www/templates/app/index.html, error at line 172
dictionary update sequence element #0 has length 1; 2 is required
172     {% for product in products %}
Traceback Switch to copy-and-paste view
/usr/lib/python2.7/dist-packages/django/core/handlers/base.py in get_response
                            response = callback(request, *callback_args, **callback_kwargs)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/contrib/auth/decorators.py in _wrapped_view
                    return view_func(request, *args, **kwargs)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/views/decorators/http.py in inner
                return func(request, *args, **kwargs)
    ...
▶ Local vars
./app/views.py in index
            context_instance=RequestContext(request))
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/shortcuts/__init__.py in render_to_response
        return HttpResponse(loader.render_to_string(*args, **kwargs), **httpresponse_kwargs)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/loader.py in render_to_string
            return t.render(context_instance)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in render
                return self._render(context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in _render
            return self.nodelist.render(context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in render
                    bit = self.render_node(node, context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/debug.py in render_node
                return node.render(context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/loader_tags.py in render
            return compiled_parent._render(context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in _render
            return self.nodelist.render(context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in render
                    bit = self.render_node(node, context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/debug.py in render_node
                return node.render(context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/loader_tags.py in render
                result = block.nodelist.render(context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in render
                    bit = self.render_node(node, context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/debug.py in render_node
                return node.render(context)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/defaulttags.py in render
            len_values = len(values)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/core/paginator.py in __len__
            return len(self.object_list)
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/db/models/query.py in __len__
                    self._result_cache = list(self.iterator())
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/db/models/query.py in iterator
                        obj = model(*row[index_start:aggregate_start])
    ...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/db/models/base.py in __init__
                    setattr(self, field.attname, val)
    ...
▶ Local vars
/usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py in __set__
                value = self.field._attribute_class(value, self.field, obj)
    ...
▶ Local vars
/usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py in __init__
            super(HStoreDictionary, self).__init__(value, **params)
    ...
▶ Local vars

当我尝试访问hstore queryset时，也会发生这种情况：

[编辑]

Traceback (most recent call last):
File "manage.py", line 14, in <module>
    execute_manager(settings)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 459, in execute_manager
    utility.execute()
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 382, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 196, in run_from_argv
    self.execute(*args, **options.__dict__)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 232, in execute
    output = self.handle(*args, **options)
File "/home/name/workspace/project/app/data/commands/my_command.py", line 60, in handle
    item_id = tmp[0].id,
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 207, in __getitem__
    return list(qs)[0]
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 87, in __len__
    self._result_cache.extend(self._iter)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 301, in iterator
    obj = model(*row[index_start:aggregate_start])
File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 300, in __init__
    setattr(self, field.attname, val)
File "/usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py", line 38, in __set__
    value = self.field._attribute_class(value, self.field, obj)
File "/usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py", line 21, in __init__
    super(HStoreDictionary, self).__init__(value, **params)
ValueError: dictionary update sequence element #0 has length 1; 2 is required

代码是：

tmp = Item.objects.where(HE("kv").contains({'key':value}))
if tmp.count() > 0:
    item_id = tmp[0].id,

我只是在尝试获取价值。我不了解“更新顺序”消息。当我使用游标而不是hstore queryset时，该函数有效。错误也来自模板渲染。我刚刚重新启动uwsgi，一切正常，但稍后又返回了错误。

回答：

刚遇到这个问题。我不知道是不是碰到了你的代码，但是对我来说，根本原因是因为我忘记name=了url（或path在Django 2.0+中）函数调用的最后一个参数。

例如，以下函数引发问题中的错误：

url(r'^foo/(?P<bar>[A-Za-z]+)/$', views.FooBar.as_view(), 'foo')
path('foo/{slug:bar}/', views.FooBar, 'foo')

但是这些实际上有效：

url(r'^foo/(?P<bar>[A-Za-z]+)/$', views.FooBar.as_view(), name='foo')
path('foo/{slug:bar}/', views.FooBar, name='foo')

回溯之所以无济于事，是因为Django在内部希望将给定的位置参数解析为关键字 arguments kwargs，并且由于字符串是可迭代的，因此非典型代码路径开始展开。始终name=在你的网址上使用！

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