Question

What is the difrence between:

1. s1 = '["a"]'

2. s2 = "['a']"

When I do json.loads, I get following error for s2 but s1 is fine:

>>> s1='["a2"]'
>>> s2="['a2']"
>>> json.loads(s1)
[u'a2']
>>> json.loads(s2)
 raise ValueError("No JSON object could be decoded")
 ValueError: No JSON object could be decoded

Answer 1

The problem is JSON uses double quotes (") for quoting values, not single ones (').

Which means the exception is thrown because of invalid JSON:

• this is invalid JSON: ['a']
• this is valid JSON: ["a"]

Also the correct example is below, different than yours:

>>> import json
>>> s1 = "['a']"
>>> s2 = '["a"]'
>>> json.loads(s1)
... some traceback removed ...
ValueError: No JSON object could be decoded
>>> json.loads(s2)
[u'a']

EDIT: I have updated the question with the correct output OP must have seen instead of what he/she posted (json.loads('["a2"]') was not throwing errors, json.loads("['a2']") was).