Python json.loads ValueError, expecting delimiter

Question

I am extracting a postgres table as json. The output file contains lines like:

{"data": {"test": 1, "hello": "I have \" !"}, "id": 4}

Now I need to load them in my python code using json.loads, but I get this error:

Traceback (most recent call last):
  File "test.py", line 33, in <module>
    print json.loads('''{"id": 4, "data": {"test": 1, "hello": "I have \" !"}}''')
  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 365, 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 381, in raw_decode
    obj, end = self.scan_once(s, idx)
ValueError: Expecting , delimiter: line 1 column 50 (char 49)

I figured out the fix is to add another \ to \". So, if I pass

{"data": {"test": 1, "hello": "I have \\" !"}, "id": 4}

to json.loads, I get this:

{u'data': {u'test': 1, u'hello': u'I have " !'}, u'id': 4}

Is there a way to do this without adding the extra \? Like passing a parameter to json.loads or something?

hey folks i am having same problem any valid solutuion ?

Afraz Ahmad
– Afraz Ahmad

2017-07-07 14:08:35 +00:00
Commented Jul 7, 2017 at 14:08 — Afraz Ahmad
– Afraz Ahmad, Commented Jul 7, 2017 at 14:08

Gandaro · Accepted Answer · 2015-01-29 19:49:26Z

30

You can specify so called “raw strings”:

>>> print r'{"data": {"test": 1, "hello": "I have \" !"}, "id": 4}'
{"data": {"test": 1, "hello": "I have \" !"}, "id": 4}

They don’t interpret the backslashes.

Usual strings change \" to ", so you can have " characters in strings that are themselves limited by double quotes:

>>> "foo\"bar"
'foo"bar'

So the transformation from \" to " is not done by json.loads, but by Python itself.

answered Jan 29, 2015 at 19:49

Gandaro

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2 Comments

AliBZ Over a year ago

I am reading the data file line by line. So I have the dictionaries in variables. I tried .replace("\\", r"\\") and .encode('string-escape'), neither works.

Gandaro Over a year ago

In JSON "\"" means '"', too, just like in Python. If there’s a \" in the input file, it actually is a ". If you for some reason want to have r'\"' anyway, you would need .replace('"', '\\"').

TylerH · Accepted Answer · 2025-03-03 15:04:34Z

9

Try this:

json.loads(r'{"data": {"test": 1, "hello": "I have \" !"}, "id": 4}')

If you have that string inside a variable, then just:

json.loads(data.replace("\\", r"\\"))

edited Mar 3 at 15:04

TylerH

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answered Jan 29, 2015 at 19:49

cdonts

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4 Comments

AliBZ Over a year ago

I'm afraid it doesn't work, '{"data": {"test": 1, "hello": "I have \" !"}, "id": 4}' and '{"data": {"test": 1, "hello": "I have \" !"}, "id": 4}'.replace("\\", r"\\") are exactly the same.

cdonts Over a year ago

@AliBZ It doesn't work because you're missing the r before the string. Copy and paste my first example, that will work.

AliBZ Over a year ago

I have my string inside a variable, thats why I used your second example.

cdonts Over a year ago

@AliBZ Ok, so the unique way to do it is manually replace " with \\" using replace.

rosa · Accepted Answer · 2021-08-16 09:34:16Z

2

Try using triple quotes r""", no need to consider the \ thing.

json_string = r"""
{
    "jsonObj": []
}
"""
data = json.loads(json_string)

answered Aug 16, 2021 at 9:34

rosa

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Comments

curry_xyd · Accepted Answer · 2017-02-17 02:35:43Z

1

Try the ways source.replace('""', '') or sub it, cause "" in the source will make json.loads(source) can not distinguish them.

answered Feb 17, 2017 at 2:35

curry_xyd

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Comments

AS Mackay · Accepted Answer · 2019-08-01 02:06:04Z

1

for my instance, i wrote:

STRING.replace("': '", '": "').replace("', '", '", "').replace("{'", '{"').replace("'}", '"}').replace("': \"", '": "').replace("', \"", '", "').replace("\", '", '", "').replace("'", '\\"')

and works like a charm.

edited Aug 1, 2019 at 2:06

AS Mackay

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answered Aug 1, 2019 at 1:46

Michael Vuolo

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