【问题标题】:Converting JSON into Python dict将 JSON 转换为 Python 字典
【发布时间】:2011-01-29 23:01:15
【问题描述】:

我一直在寻找这个问题的答案,但我似乎无法找到它。可能到了晚上想不出答案已经太晚了,所以我转向这里的优秀读者。

我从 CouchDB 记录中提取了以下一些 JSON 数据:

"{\"description\":\"fdsafsa\",\"order\":\"1\",\"place\":\"22 Plainsman Rd, Mississauga, ON, Canada\",\"lat\":43.5969175,\"lng\":-79.7248744,\"locationDate\":\"03/24/2010\"},{\"description\":\"sadfdsa\",\"order\":\"2\",\"place\":\"50 Dawnridge Trail, Brampton, ON, Canada\",\"lat\":43.7304774,\"lng\":-79.8055435,\"locationDate\":\"03/26/2010\"},"

此数据存储在名为“my_plan”的字典中的关键字“locations”下的 Python 字典中。我想将这些数据从 CouchDB 转换为 Python 字典,以便可以在 Django 模板中执行以下操作:

{% for location in my_plan.locations %}                                                           
<tr>
    <td>{{ location.place }}</td>
    <td>{{ location.locationDate }}</td>
</tr>

{% endfor %}

我找到了很多关于将 dicts 转换为 JSON 的信息,但没有找到其他方式。

【问题讨论】:

    标签: python django json dictionary


    【解决方案1】:

    第一件事第一

    在这里,我将您提取的数据字符串存储到一个名为data_str的变量中,该变量有两个字典

    >>> data_str = "{\"description\":\"fdsafsa\",\"order\":\"1\",\"place\":\"22 Plainsman Rd, Mississauga, ON, Canada\",\"lat\":43.5969175,\"lng\":-79.7248744,\"locationDate\":\"03/24/2010\"},{\"description\":\"sadfdsa\",\"order\":\"2\",\"place\":\"50 Dawnridge Trail, Brampton, ON, Canada\",\"lat\":43.7304774,\"lng\":-79.8055435,\"locationDate\":\"03/26/2010\"},"
    

    之后,我将其转换为另一个名为 data_str2 的字符串,该字符串采用 list 形式,并从末尾删除了多余的逗号(,)(如它给出了error而字符串数据到python对象的转换)。

    >>> data_str2 = "[" + data_str[0: 1] + data_str[1: len(data_str)-1] + "]"
    

    最后,我将这个 list string(一个包含 2 个字典的列表)转换为原始 python list 并将其存储在一个名为 data_list 的变量中.

    >>> import json
    >>> data_list = json.loads(data_str2) # Now data_list is a list having 2 dictionaries
    

    现在让我们打印我们的数据。

    >>> print data_list
    [{u'description': u'fdsafsa', u'order': u'1', u'place': u'22 Plainsman Rd, Mississauga, ON, Canada', u'lat': 43.5969175, u'lng': -79.7248744, u'locationDate': u'03/24/2010'}, {u'description': u'sadfdsa', u'order': u'2', u'place': u'50 Dawnridge Trail, Brampton, ON, Canada', u'lat': 43.7304774, u'lng': -79.8055435, u'locationDate': u'03/26/2010'}]
    >>> 
    >>> print type(data_list)
    <type 'list'>
    >>> 
    >>> print data_list[0]
    {u'description': u'fdsafsa', u'order': u'1', u'place': u'22 Plainsman Rd, Mississauga, ON, Canada', u'lat': 43.5969175, u'lng': -79.7248744, u'locationDate': u'03/24/2010'}
    >>> 
    >>> print data_list[1]
    {u'description': u'sadfdsa', u'order': u'2', u'place': u'50 Dawnridge Trail, Brampton, ON, Canada', u'lat': 43.7304774, u'lng': -79.8055435, u'locationDate': u'03/26/2010'}
    >>> 
    

    从视图中传递这个 data_list 列表并在您的 Django 模板 中访问它,如下所示,

    {% for data in locations %}
          <tr>
               <td> {{ data.place }} </td>
               <td> {{ data.locationDate }} </td>
          </tr>
    {% endfor %}
    

    供您查看的示例代码段。

    def locations(request):
        # YOU HAVE TO WRITE YOUR CODE LOGIC HERE TO GET THE LIST, 
        # I AM WRITING IT DIRECTLY
        data_list = [{u'description': u'fdsafsa', u'order': u'1', u'place': u'22 Plainsman Rd, Mississauga, ON, Canada', u'lat': 43.5969175, u'lng': -79.7248744, u'locationDate': u'03/24/2010'}, {u'description': u'sadfdsa', u'order': u'2', u'place': u'50 Dawnridge Trail, Brampton, ON, Canada', u'lat': 43.7304774, u'lng': -79.8055435, u'locationDate': u'03/26/2010'}]
        return render(request, "locations.html", {"locations": data_list})
    

    效果不错。

    现在我想解释我是如何找到解决方案的,我认为这对初学者会有帮助。请参阅下面解释的逐步过程或see here

    >>> import json   
    >>>
    >>> # A simple attempt
    >>> s = "{\"description\":\"fdsafsa\"}"
    >>> python_dict = json.loads(s)
    >>> python_dict
    {u'description': u'fdsafsa'}
    >>> # Accessing value using key
    >>> python_dict["description"]
    u'fdsafsa'
    >>> 
    >>> # It worked, lets test our given string containing 2 dictionaries(in string form) one by one
    >>> # Converting 1st JSON string to Dict
    >>> s2 = "{\"description\":\"fdsafsa\",\"order\":\"1\",\"place\":\"22 Plainsman Rd, Mississauga, ON, Canada\",\"lat\":43.5969175,\"lng\":-79.7248744,\"locationDate\":\"03/24/2010\"}"
    >>> python_dict2 = json.loads(s2)                                                                                      >>> python_dict2
    {u'description': u'fdsafsa', u'order': u'1', u'place': u'22 Plainsman Rd, Mississauga, ON, Canada', u'lat': 43.5969175, u'lng': -79.7248744, u'locationDate': u'03/24/2010'}
    >>> 
    >>> # Converting 2nd JSON string to Dict
    >>> # remove comma(,) from end otherwise you will get the following error
    >>> s3 = "{\"description\":\"sadfdsa\",\"order\":\"2\",\"place\":\"50 Dawnridge Trail, Brampton, ON, Canada\",\"lat\":43.7304774,\"lng\":-79.8055435,\"locationDate\":\"03/26/2010\"},"
    >>> python_dict3 = json.loads(s3)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 339, in loads
        return _default_decoder.decode(s)
      File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 367, in decode
        raise ValueError(errmsg("Extra data", s, end, len(s)))
    ValueError: Extra data: line 1 column 152 - line 1 column 153 (char 151 - 152)
    >>> 
    >>> # Now I removed comma(,) from end and retried, it worked
    >>> s3 = "{\"description\":\"sadfdsa\",\"order\":\"2\",\"place\":\"50 Dawnridge Trail, Brampton, ON, Canada\",\"lat\":43.7304774,\"lng\":-79.8055435,\"locationDate\":\"03/26/2010\"}"
    >>> python_dict3 = json.loads(s3) 
    >>> 
    >>> # So now we knew that we have not to include any extra comma at end in the string form of JSON
    >>> # For example (Correct form)
    >>> details_str = "{\"name\":\"Rishikesh Agrawani\", \"age\": 25}" 
    >>> details_dict = json.loads(details_str)
    >>> details_dict["name"]
    u'Rishikesh Agrawani'
    >>> details_dict["age"]
    25
    >>> # Now (Incorrect form), here comma(,) is at end, just after } 
    >>> details_str = "{\"name\":\"Rishikesh Agrawani\", \"age\": 25},"
    >>> details_dict = json.loads(details_str)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 339, in loads
        return _default_decoder.decode(s)
      File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 367, in decode
        raise ValueError(errmsg("Extra data", s, end, len(s)))
    ValueError: Extra data: line 1 column 41 - line 1 column 42 (char 40 - 41)
    >>> 
    >>> # The problem is the string does not denote any single python object 
    >>> # So we will convert the string into a list form by appending [ at beginning and ] at end
    >>> # Now our string will denote a single Python object that is list of 2 dictioanaries
    >>> # Lets do this, here I am storing the given string into variable s4
    >>> data_str = "{\"description\":\"fdsafsa\",\"order\":\"1\",\"place\":\"22 Plainsman Rd, Mississauga, ON, Canada\",\"lat\":43.5969175,\"lng\":-79.7248744,\"locationDate\":\"03/24/2010\"},{\"description\":\"sadfdsa\",\"order\":\"2\",\"place\":\"50 Dawnridge Trail, Brampton, ON, Canada\",\"lat\":43.7304774,\"lng\":-79.8055435,\"locationDate\":\"03/26/2010\"},"
    >>> s5 = "[" + s4[0:1] + s4[1: len(s4)-1] + "]"
    >>> s5
    '[{"description":"fdsafsa","order":"1","place":"22 Plainsman Rd, Mississauga, ON, Canada","lat":43.5969175,"lng":-79.7248744,"locationDate":"03/24/2010"},{"description":"sadfdsa","order":"2","place":"50 Dawnridge Trail, Brampton, ON, Canada","lat":43.7304774,"lng":-79.8055435,"locationDate":"03/26/2010"}]'
    >>> # l is a list of 2 dictionaries
    >>> l = json.loads(s5)
    >>> l[0]
    {u'description': u'fdsafsa', u'order': u'1', u'place': u'22 Plainsman Rd, Mississauga, ON, Canada', u'lat': 43.5969175, u'lng': -79.7248744, u'locationDate': u'03/24/2010'}
    >>> 
    >>> l[1]
    {u'description': u'sadfdsa', u'order': u'2', u'place': u'50 Dawnridge Trail, Brampton, ON, Canada', u'lat': 43.7304774, u'lng': -79.8055435, u'locationDate': u'03/26/2010'}
    >>>                                                           
    

    谢谢

    【讨论】:

      【解决方案2】:

      只是其他答案的组合:

      import json
      yourString = "{\"description\":\"fdsafsa\",\"order\":\"1\",\"place\":\"22 Plainsman Rd, Mississauga, ON, Canada\",\"lat\":43.5969175,\"lng\":-79.7248744,\"locationDate\":\"03/24/2010\"},{\"description\":\"sadfdsa\",\"order\":\"2\",\"place\":\"50 Dawnridge Trail, Brampton, ON, Canada\",\"lat\":43.7304774,\"lng\":-79.8055435,\"locationDate\":\"03/26/2010\"},"
      target = json.loads("[" + yourString[:-1] + "]")
      

      输出

      [{u'description': u'fdsafsa', u'order': u'1', u'place': u'22 Plainsman Rd, Mississauga, ON, Canada', u'lat': 43.5969175, u'lng': -79.7248744, u'locationDate': u'03/24/2010'}, {u'description': u'sadfdsa', u'order': u'2', u'place': u'50 Dawnridge Trail, Brampton, ON, Canada', u'lat': 43.7304774, u'lng': -79.8055435, u'locationDate': u'03/26/2010'}]
      

      如前所述

      • 这个字符串包含两个json对象,所以把它放在一个数组中([]
      • 它有一个尾随,,通过[:-1] 切片语法删除

      【讨论】:

        【解决方案3】:
        Hello here my example
        import json
        class SimpleObject(object):
            def __init__(self, _dict):
                self.__dict__.update(_dict)
        
        data=json.loads("{\"name\":\"Rishikesh Agrawani\", \"age\": 25}" )  
        so=SimpleObject(data)
        print (so.name)
        print (so.age)
        
        if you transform your data to objects is better and more fast work.
        

        【讨论】:

          【解决方案4】:

          您显示的字符串不是 JSON 编码的对象(eqv 到 Python dict)——更像是一个数组(eqv 到列表),没有括号,末尾有一个额外的逗号。所以(使用simplejson 实现版本可移植性——2.6 中标准库的json 当然也可以!-):

          >>> import simplejson
          >>> js = "{\"description\":\"fdsafsa\",\"order\":\"1\",\"place\":\"22 Plainsman Rd, Mississauga, ON, Canada\",\"lat\":43.5969175,\"lng\":-79.7248744,\"locationDate\":\"03/24/2010\"},{\"description\":\"sadfdsa\",\"order\":\"2\",\"place\":\"50 Dawnridge Trail, Brampton, ON, Canada\",\"lat\":43.7304774,\"lng\":-79.8055435,\"locationDate\":\"03/26/2010\"},"
          >>> simplejson.loads('[%s]' % js[:-1])
          [{'description': 'fdsafsa', 'order': '1', 'place': '22 Plainsman Rd, Mississauga, ON, Canada', 'lat': 43.596917500000004, 'lng': -79.724874400000004, 'locationDate': '03/24/2010'}, {'description': 'sadfdsa', 'order': '2', 'place': '50 Dawnridge Trail, Brampton, ON, Canada', 'lat': 43.730477399999998, 'lng': -79.805543499999999, 'locationDate': '03/26/2010'}]
          

          如果你真的想要一个 dict,你必须指定如何处理这两个未命名的项目,即,你想给它们敲什么任意键......?

          【讨论】:

          • 您的解决方案完美运行。谢谢!我将在数据进入 CouchDB 之前修复生成该数据的例程,以便不附加额外的逗号。有点深夜编码马虎
          • @Grumpy,当然——如果我是你,我也会在数据库中的字符串周围加上方括号,以确保它是有效的 JSON,而不是接收方的“有点不完整的 JSON”代码必须完成。
          • 我以前这样做过,但不记得为什么我停止这样做了……我认为从现在开始深夜编码需要笔记
          • 为什么不使用 json 模块? simplejson 是遗留的,很久以前就应该弃用了。检查下面的答案为什么:)
          【解决方案5】:
          • 使用 json 模块加载 JSON。 (Pre-2.6 使用第三方simplejson 模块,API 完全相同。)

            >>> import json
            >>> s = '{"foo": 6, "bar": [1, 2, 3]}'
            >>> d = json.loads(s)
            >>> print d
            {u'foo': 6, u'bar': [1, 2, 3]}
            
          • 您的实际数据无法以这种方式加载,因为它实际上是两个 JSON 对象,由逗号分隔并以逗号结尾。您需要将它们分开或以其他方式处理。

            • 你从哪里得到这个字符串?

          【讨论】:

          • 该字符串来自我正在开发的应用程序生成的数据,这是一种用于计划旅行、酒吧爬行等的位置和日期社交应用程序
          【解决方案6】:
          django.utils.simplejson.loads(someJson)
          

          【讨论】:

          • 不转换为字典。我确实尝试过;)
          • 它给出的实际错误是“额外数据:第 1 行第 151 列 - 第 1 行第 304 列(字符 151 - 304)”
          • @GrumpyCanuck,仔细看。这不是一个对象。它是一个对象,然后是一个逗号,然后是一个对象,然后是一个逗号。
          • 是的,当我看到@Alex Martelli 的回答时我就明白了
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