Home/ Questions/Is there any solution for the dictionary update sequence element #0 has length 1; 2 is required error?
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Keanu Gagnon
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Asked: 2022-05-17T13:53:20+00:00 In:

Is there any solution for the dictionary update sequence element #0 has length 1; 2 is required error?

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I am tired of fixing the problem: dictionary update sequence element #0 has length 1; 2 is required in the python; even if I get the reference from another forum, it still returns an error:

dictionary update sequence element #0 has length 1; 2 is required

To identify the problem, I will show you the detail here:

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

How do I do that? Could you support me in improving this problem?

dictionary update sequence element
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2 Answers

  1. Best Answer
    Expert

    The cause:

    Through the below code, we can easily see the reason of this error is due to you are having problem with string and dictionary.

    dict1 = {'taras': 'vaskiv', 'iruna': 'vaskiv'}
str1 = str(dict1)
dict(str1)
*** ValueError: dictionary update sequence element #0 has length 1; 2 is required

    Solution:

    This problem can be solved by getting dict from string:

    dic2 = eval(str1)
dic2
{'taras': 'vaskiv', 'iruna': 'vaskiv'}

    Or you can use literal_eval for matter of security:

    from ast import literal_eval
    • 19

  2. This is the problem I encountered. It’s possible that it is the same problem as your code. However, I believe the root cause was name= not being placed on the last argument in the url function call (or path for Django 2.0+).

    The following functions, for example, throw an error in the question 

    url(r'^foo/(?P<bar>[A-Za-z]+)/
 
    
  These actually work.
 
    
  
    url(r'^foo/(?P<bar>[A-Za-z]+)/
 
    
  Django internally wants to parse the given  argument as kwargs. Since a string is an Iterable, it is possible to create an unusual code path. Use name= for your urls
 
    

    

    

    , views.FooBar.as_view(), 'foo')
    
path('foo/{slug:bar}/', views.FooBar, 'foo')

    These actually work.

    codeTagPre12

    Django internally wants to parse the given argument as kwargs. Since a string is an Iterable, it is possible to create an unusual code path. Use name= for your urls

    , views.FooBar.as_view(), name='foo')
    path('foo/{slug:bar}/', views.FooBar, name='foo')

    Django internally wants to parse the given argument as kwargs. Since a string is an Iterable, it is possible to create an unusual code path. Use name= for your urls

    , views.FooBar.as_view(), ‘foo’)
    path(‘foo/{slug:bar}/’, views.FooBar, ‘foo’)

    These actually work. 

    url(r'^foo/(?P<bar>[A-Za-z]+)/
 
    
  Django internally wants to parse the given  argument as kwargs. Since a string is an Iterable, it is possible to create an unusual code path. Use name= for your urls

    , views.FooBar.as_view(), name='foo')
    path('foo/{slug:bar}/', views.FooBar, name='foo')

    Django internally wants to parse the given argument as kwargs. Since a string is an Iterable, it is possible to create an unusual code path. Use name= for your urls

    • 8

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