CODEWITHSUNDEEP
pythonjsonfile
Flying Thunder
Flying Thunder

Reputation: 940

Python - cant import from JSON?

i have one class dumping a list containing strings into a .json file and another class loading this file. However i am getting weird errors that i dont understand - this is the content of the .json file (example): ["1", "1", "1", "1", "1", "1", "1", "11", "1", "1", "1.1.1.1", "11.11.11.11"]

This is the code that reads the .json file in another class:

 with open('test.json','a+') as infile:
        if os.stat('test.json').st_size != 0:
            jsonimport = json.load(infile)

I was thinking that open() in Python does not create a file if it doesn't exist is related, but im not reading the file normally but instead using JSON to load the data...

This is the Error:

    File "C:\Users\Administrator\Documents\QTTestGIT\IPv4calc.py", line 12, in __init__
    self.CallPrompt()
  File "C:\Users\Administrator\Documents\QTTestGIT\IPv4calc.py", line 18, in CallPrompt
    jsonimport = json.load(infile)
  File "C:\Program Files\Python36\lib\json\__init__.py", line 299, in load
    parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
  File "C:\Program Files\Python36\lib\json\__init__.py", line 354, in loads
    return _default_decoder.decode(s)
  File "C:\Program Files\Python36\lib\json\decoder.py", line 339, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "C:\Program Files\Python36\lib\json\decoder.py", line 357, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Process finished with exit code 1

Upvotes: 0

Views: 2131

Answers (1)

DeepSpace
DeepSpace

Reputation: 81604

It does not work because you are using the a+ mode to open the file.

json.load uses the .read method of the passed file-like object. Since you are using a+ mode, .read will return an empty string (which makes sense as the cursor will be at the end of the file).

Change mode to r (or don't provide any mode, r is the default) and your code will work.

Alternatively, you can call infile.seek(0) before calling json.load but then I don't see the point of using a+ mode to begin with.

import json

file_name = 'test.json'

with open(file_name, 'a+') as infile:
    if os.stat(file_name).st_size != 0:
        infile.seek(0)
        print(json.load(infile))
        # ['1', '1', '1', '1', '1', '1', '1', '11', '1', '1', '1.1.1.1', '11.11.11.11']

Upvotes: 1

Related Questions