Converting JSON into Python dict_问答_开发者_运维开发者技术经验分享

I've been searching around trying to find an answer to this question, and I can't seem to track it down. Maybe it's too late in the evening to figure the answer out, so I turn to the excellent readers here.

I have the following bit of JSON data that I a开发者_StackOverflow社区m pulling out of a CouchDB record:

"{\"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\"},"

This data is stored inside a Python dict under the key 'locations' in a dict called 'my_plan'. I want to covert this data from CouchDB into a Python dict so I can do the following in a Django template:

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

{% endfor %}

I've found lots of info on converting dicts to JSON, but nothing on going back the other way.

Use the json module for loading JSON. (Pre-2.6 use the third party simplejson module, which has the same exact API.)

>>> import json
>>> s = '{"foo": 6, "bar": [1, 2, 3]}'
>>> d = json.loads(s)
>>> print d
{u'foo': 6, u'bar': [1, 2, 3]}

Your actual data cannot be loaded this way since it's actually two JSON objects separated by a comma and with a trailing comma. You'll need to separate them or otherwise deal with this.
- Where did you get this string?

The string you show is not a JSON-coded object (eqv to a Python dict) — more like an array (eqv to a list) without brackets and with a stray extra comma at the end. So (using simplejson for version portability — the standard library's json in 2.6 is fine too of course!-):

>>> 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'}]

If you really want a dict you'll have to specify how to treat these two unnamed items, i.e., what arbitrary keys you want to slap on them...?

django.utils.simplejson.loads(someJson)

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.

Just a combination of other answers:

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] + "]")

outputs

[{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'}]

As mentioned

this string contains two json objects, so put it inside an array (the [])
it has a trailing ,, remove via [:-1] slicing syntax

First thing first.

Here I have stored your pulled data string into a variable named data_str which has two dictionaries.

>>> 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\"},"

After that I converted it into another string named data_str2 which is in list form and removed extra comma(,) from end (as it gives error while string data to python object conversion).

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

Finally, I converted this list string (a list having 2 dictionaries) into original python list and stored it in a variable named data_list.

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

Now let's print our data.

>>> 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'}
>>>

Pass this data_list list from views and access it in your Django template as follows,

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

A sample code segment for your views.

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})

IT WORKED NICE.

Now I wanna explain that how I reached to solution, I think it will be helpful for beginners. Please see the below explained step by step procedure or 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'}
>>>

Thanks.