Python : How to write json formatted string in json file

Question

I have a requirement where I have to write some JSON string in a file.

For example, I have below string in

My python code :

 S = '''{
"K1": "v1",
"K2" : "\nv2"
}'''

When I try to write it in json file using json.dumps(s) it is getting written to a file like below :

"{\"k1\" : \"v1\",\"k2\" : \"\\nv2\"}"

Whereas I need it to be like :

 {
"K1": "v1",
"K2" : "\nv2"
}

In json file.

I am able to achieve this if I declare my string as raw string preceding with r but In the actual scenario I cannot declare a raw string as I am getting the string value in python variable.

Note: I am having multiple escape sequences in my json string value like given in value for key k2 in the above json structure.

Will really appreciate it if anyone helps me to generate a proper json file with required json format.Thanks in advance.

stackoverflow.com/questions/25242262/… -- possible solution — Rajat Mishra
– Rajat Mishra, Commented Apr 13, 2020 at 16:06
@Rajat Mishra - It didn't worked for me as I cannot convert string data to dictionary. Is there any way I can create variables with raw string as its values? — Anvita
– Anvita, Commented Apr 13, 2020 at 16:09

Rajat Mishra · Accepted Answer · 2020-04-13 16:28:38Z

2

Declare your variable as

S = {
"K1": "v1",
"K2" : "\nv2"
}

Then it would work. For example:

In [16]: s
Out[16]: {'K1': 'v1', 'K2': '\nv2'}

In [17]: st = json.dumps(s)

In [18]: st
Out[18]: '{"K1": "v1", "K2": "\\nv2"}'

In [19]: s1 = '''{
    ...: "K1": "v1",
    ...: "K2" : "\nv2"
    ...: }'''

In [20]: st1 = json.dumps(s1)

In [21]: st1
Out[21]: '"{\\n\\"K1\\": \\"v1\\",\\n\\"K2\\" : \\"\\nv2\\"\\n}"'

Update: If your data is coming as string, first convert it into dictionary using json.loads(). For example:

In [24]: st
Out[24]: '{"K1": "v1", "K2": "\\nv2"}'

In [25]: json.loads(st)
Out[25]: {'K1': 'v1', 'K2': '\nv2'}

In [26]: json.dumps(json.loads(st))
Out[26]: '{"K1": "v1", "K2": "\\nv2"}'

edited Apr 13, 2020 at 16:28

answered Apr 13, 2020 at 16:15

Rajat Mishra

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3 Comments

Anvita Over a year ago

I cannot declare string as dictionary.Data is coming as string.

Rajat Mishra Over a year ago

In that case, use the json.loads() to convert dictionary string to dictionary.

Anvita Over a year ago

Thanks I used json.loads() with strict flag and it worked!

Anvita · Accepted Answer · 2020-04-15 06:46:43Z

I get it working for my specific requirement using below modifications python3.6 code:

py_string = '''{ "k1":"v1","k2":"\nv2"}'''
valid_json_string = json.dumps(json.loads(py_string ,strict=False))
with open('test.json', 'w') as outfile:
     json.dump(valid_json_string, outfile)

With this lines of code I was able to write this json string in json file without having escaped double quotes and strings.

Basically, when we paste the json contents directly to assign it to python string,Python will not allow the json valid control characters in string.python string will escape the special control characters like \n will treat as newline.

So to allow it in python string json.loads() supports "strict" flag. If strict is false (True is the default), then control characters will be allowed inside strings. Control characters in this context are those with character codes in the 0–31 range, including '\t' (tab), '\n', '\r' and '\0'.

For more info - https://docs.python.org/3/library/json.html

Brian · Accepted Answer · 2021-10-01 14:40:16Z

0

If you want an easy way to do it you can use jsonwriter
for example:

# pip install jsonwriter
from jsonwriter import file

file = file('yourfilename.json', autosave=True)

file.set('K1', 'v1')
file.set('K2', '\nv2')
# And it will be saved automatically

for more info checkout jsonwriter docs

answered Oct 1, 2021 at 14:40

Brian

1

1 Comment

Matthew Barlowe Over a year ago

How is this module better than using the built in json python module?

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