在 Python 中将 JSON 转换为字符串

我一开始没有把我的问题解释清楚。 在 python 中将 JSON 转换为 string 时,请尝试使用 str()json.dumps()

>>> data = {'jsonKey': 'jsonValue',"title": "hello world"}
>>> print json.dumps(data)
{"jsonKey": "jsonValue", "title": "hello world"}
>>> print str(data)
{'jsonKey': 'jsonValue', 'title': 'hello world'}
>>> json.dumps(data)
'{"jsonKey": "jsonValue", "title": "hello world"}'
>>> str(data)
"{'jsonKey': 'jsonValue', 'title': 'hello world'}"

我的问题是:

>>> data = {'jsonKey': 'jsonValue',"title": "hello world'"}
>>> str(data)
'{\'jsonKey\': \'jsonValue\', \'title\': "hello world\'"}'
>>> json.dumps(data)
'{"jsonKey": "jsonValue", "title": "hello world\'"}'
>>>

我的预期输出: "{'jsonKey': 'jsonValue','title': 'hello world''}"

>>> data = {'jsonKey': 'jsonValue',"title": "hello world""}
File "<stdin>", line 1
data = {'jsonKey': 'jsonValue',"title": "hello world""}
^
SyntaxError: EOL while scanning string literal
>>> data = {'jsonKey': 'jsonValue',"title": "hello world\""}
>>> json.dumps(data)
'{"jsonKey": "jsonValue", "title": "hello world\\""}'
>>> str(data)
'{\'jsonKey\': \'jsonValue\', \'title\': \'hello world"\'}'

我的预期输出: "{'jsonKey': 'jsonValue','title': 'hello world\"'}"

对于我来说,没有必要再次将输出字符串更改为 json (dict)。

怎么做?

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json.dumps() is much more than just making a string out of a Python object, it would always produce a valid JSON string (assuming everything inside the object is serializable) following the Type Conversion Table.

For instance, if one of the values is None, the str() would produce an invalid JSON which cannot be loaded:

>>> data = {'jsonKey': None}
>>> str(data)
"{'jsonKey': None}"
>>> json.loads(str(data))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 338, in loads
return _default_decoder.decode(s)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 366, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 382, in raw_decode
obj, end = self.scan_once(s, idx)
ValueError: Expecting property name: line 1 column 2 (char 1)

But the dumps() would convert None into null making a valid JSON string that can be loaded:

>>> import json
>>> data = {'jsonKey': None}
>>> json.dumps(data)
'{"jsonKey": null}'
>>> json.loads(json.dumps(data))
{u'jsonKey': None}

There are other differences. For instance, {'time': datetime.now()} cannot be serialized to JSON, but can be converted to string. You should use one of these tools depending on the purpose (i.e. will the result later be decoded).