错误:无法散列的类型:'dict' [英] Error: unhashable type: 'dict'

问题描述

我对Django有问题:我无法在表中显示mysql数据库中的数据.我看到错误异常值:不可哈希类型:'dict'"这是我的代码:views.py:

i have a problem with Django: I can't show the data from mysql database in the table. I see the error "Exception Value: unhashable type: 'dict'" This is my code: views.py:

List_of_date=El.objects.all()
return HttpResponse(template.render(context),args, {'List_of_date': List_of_date})

models.py:

models.py:

class El(models.Model):
    id_ch=models.IntegerField()
    TXT = models.CharField(max_length=200) 

模板:

<table>
    <thead>
    <tr>
        <th>№</th>
        <th>Text</th>
    </tr>
    </thead>
    <tbody>
   {% for i in List_of_date %}
    <tr>
        <td class="center">{{ i.id_ch }}</td>
        <td class="center">{{ i.TXT }}</td>
    </tr>
       {% endfor %}
    </tbody>
    </table>

有人可以帮助我吗?

推荐答案

通常什么时候会出现无法散列的类型:"dict" 错误?

When do you generally get an unhashable type: 'dict' error?

当您尝试使用字典作为键来在另一个字典中执行查找时，会出现此错误.

When you try to use a dictionary as a key to perform lookup in another dictionary, you get this error.

例如:

In [1]: d1 = {'a':1, 'b':2}

In [2]: d2 = {'c':3}

In [3]: d2[d1] # perform lookup with key as dictionary 'd1'
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-3-163d2a314f4b> in <module>()
----> 1 d2[d1]

TypeError: unhashable type: 'dict'

为什么会出现此错误?

这是因为您创建 @所指出的实例时，将错误的参数传递给 HttpResponse 类弗朗西斯.

This is because you have passed wrong arguments to HttpResponse class when creating its instance as pointed out by @Francis.

当您执行 HttpResponse(template.render(context)，args，{'List_of_date':List_of_date})时， template.render(context)成为 content ， args 成为 content_type ，而字典 {'List_of_date':List_of_date} 成为 status .

When you do HttpResponse(template.render(context), args, {'List_of_date': List_of_date}), then template.render(context) becomes content, args becomes the content_type and the dictionary {'List_of_date': List_of_date} becomes the status of the response object.

现在在内部，Django根据响应对象的 status 执行查找，以在响应对象上设置 reason_phrase .由于 status 不是整数而是字典，因此会发生上述错误.

Now internally, Django performs a lookup based on the status of the response object to set the reason_phrase on response object. Since the status is not an integer but a dictionary, the above error occurs.

解决方案:

您需要使用 render() @Daniel 快捷方式也可以很完美去做.

You need to use render() shortcut provided by Django instead as @Daniel also mentioned which is perfect for what you are intending to do.

它将为您呈现模板，并使用 RequestContext 实例自动呈现模板.您可以执行以下操作:

It will render the template for you and automatically render the template with RequestContext instance. You can do something like:

return render(template_name, {'List_of_date': List_of_date})

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