json.loads(...) ValueError: Expecting value: line 1 column 1 (char 0)
Ben Bacarisse
ben.usenet at bsb.me.uk
Mon May 9 16:41:48 EDT 2016
zljubisic at gmail.com writes:
> in python3 my variable looks like this:
>
> a = b'{"uuid":"5730e8666ffa02.34177329","error":""}'
> str(a) = 'b\'{"uuid":"5730e8666ffa02.34177329","error":""}\''
>
> If I execute the following command I get the error:
>
>>>> json.loads(str(a))
> Traceback (most recent call last):
> File "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 2016.1.2\helpers\pydev\_pydevd_bundle\pydevd_exec2.py", line 3, in Exec
> exec(exp, global_vars, local_vars)
> File "<input>", line 1, in <module>
> File "C:\Program Files\Python34\lib\json\__init__.py", line 318, in loads
> return _default_decoder.decode(s)
> File "C:\Program Files\Python34\lib\json\decoder.py", line 343, in decode
> obj, end = self.raw_decode(s, idx=_w(s, 0).end())
> File "C:\Program Files\Python34\lib\json\decoder.py", line 361, in raw_decode
> raise ValueError(errmsg("Expecting value", s, err.value)) from None
> ValueError: Expecting value: line 1 column 1 (char 0)
>
> Why I am getting this error?
The result of str(a) is not a valid JSON string. It starts with a b but
a JSON string must start with a digit of one of -, ", {, [, t, f, n (the
letters being legal only if they are the start of true, false or null.
In fact (in Python 3), passing bytes to str() without an encoding is a
special case -- you get an informal string representation. I'm not sure
you can be sure what you get though I imagine it's designed to be the
same as Python 2 gave.
> If I set variable a to the
> '{"uuid":"5730e8666ffa02.34177329","error":""}' everything works as
> expected.
That string starts with { so it's OK. You probably what something like
json.loads(str(a, 'ascii'))
or maybe 'utf-8' or 'windows-1285' or... well you get the idea. You
need to say how the bytes should be turned into string characters.
--
Ben.
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