Andres Andres - 4 months ago 15
JSON Question

Reading JSON file with Python 3

I'm using Python 3.5.2 on Windows 10 x64. The

JSON
file I'm reading is this which is a
JSON
array containing 2 more arrays.

I'm trying to parse this
JSON
file using the
json
module. As described in the docs the
JSON
file must be compliant to
RFC 7159
. I checked my file here and it tells me it's perfectly fine with the
RFC 7159
format, but when trying to read it using this simple python code:

with open(absolute_json_file_path, encoding='utf-8-sig') as json_file:
text = json_file.read()
json_data = json.load(json_file)
print(json_data)


I'm getting this exception:

Traceback (most recent call last):
File "C:\Program Files (x86)\JetBrains\PyCharm 4.0.5\helpers\pydev\pydevd.py", line 2217, in <module>
globals = debugger.run(setup['file'], None, None)
File "C:\Program Files (x86)\JetBrains\PyCharm 4.0.5\helpers\pydev\pydevd.py", line 1643, in run
pydev_imports.execfile(file, globals, locals) # execute the script
File "C:\Program Files (x86)\JetBrains\PyCharm 4.0.5\helpers\pydev\_pydev_imps\_pydev_execfile.py", line 18, in execfile
exec(compile(contents+"\n", file, 'exec'), glob, loc)
File "C:/Users/Andres Torti/Git-Repos/MCF/Sur3D.App/shapes-json-checker.py", line 14, in <module>
json_data = json.load(json_file)
File "C:\Users\Andres Torti\AppData\Local\Programs\Python\Python35-32\lib\json\__init__.py", line 268, in load
parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
File "C:\Users\Andres Torti\AppData\Local\Programs\Python\Python35-32\lib\json\__init__.py", line 319, in loads
return _default_decoder.decode(s)
File "C:\Users\Andres Torti\AppData\Local\Programs\Python\Python35-32\lib\json\decoder.py", line 339, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "C:\Users\Andres Torti\AppData\Local\Programs\Python\Python35-32\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)


I can read this exact file perfectly fine on Javascript but I can't get Python to parse it. Is there anything wrong with my file or is any problem with the Python parser?

Answer

Based on reading over the documentation again, it appears you need to either change the third line to

json_data = json.loads(text)

or remove the line

text = json_file.read()

since read() causes the file's index to reach the end of the file. (I suppose, alternatively, you can reset the index of the file).