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[ Decode complex JSON in Python ]

Hey, I have a JSON object created in PHP, that JSON object contains another escaped JSON string in one of it's cells:

php > $insidejson = array('foo' => 'bar','foo1' => 'bar1');
php > $arr = array('a' => array('a1'=>json_encode($insidejson)));
php > echo json_encode($arr);

Then, with Python, I try deocding it using simplejson:

>>> import simplejson as json
>>> json.loads('{"a":{"a1":"{\"foo\":\"bar\",\"foo1\":\"bar1\"}"}}')

This fails with the following error:

Traceback (most recent call last):
  File "", line 1, in ?
  File "build/bdist.linux-i686/egg/simplejson/__init__.py", line 307, in loads
  File "build/bdist.linux-i686/egg/simplejson/decoder.py", line 335, in decode
  File "build/bdist.linux-i686/egg/simplejson/decoder.py", line 351, in raw_decode
ValueError: Expecting , delimiter: line 1 column 14 (char 14)

How can I get this JSON object decoded in Python? Both PHP and JS decode it successfully and I can't change it's structure since that would require major changes in many different components in different languages.


Answer 1

Try prefixing your string with 'r' to make it a raw string:

# Python 2.6.2
>>> import json
>>> s = r'{"a":{"a1":"{\"foo\":\"bar\",\"foo1\":\"bar1\"}"}}'
>>> json.loads(s)
{u'a': {u'a1': u'{"foo":"bar","foo1":"bar1"}'}}

What Alex says below is true: you can just double the slashes. (His answer was not posted when I started mine.) I think that using raw strings is simpler, if only because it's a language feature that means the same thing and it's harder to get wrong.

Answer 2


Maybe simplejson is too much "simple".

Answer 3

If you want to insert backslashes into a string they need escaping themselves.

import simplejson as json

I've tested it and Python handles that input just fine - except I used the json module included in the standard library (import json, Python 3.1).