显示比无法解码 JSON 对象更好的错误消息

Python code to load data from some long complicated JSON file:

with open(filename, "r") as f:
  data = json.loads(f.read())

(注:最佳代码版本应为:

with open(filename, "r") as f:
  data = json.load(f)

但两者表现出相似的行为)

对于许多类型的JSON错误(缺少分隔符、字符串中的反斜杠不正确等)，这将打印一条很有帮助的消息，其中包含发现JSON错误的行号和列号.

However, for other types of JSON error (including the classic "using comma on the last item in a list", but also other things like capitalising true/false), Python's output is just:

Traceback (most recent call last):
  File "myfile.py", line 8, in myfunction
    config = json.loads(f.read())
  File "c:\python27\lib\json\__init__.py", line 326, in loads
    return _default_decoder.decode(s)
  File "c:\python27\lib\json\decoder.py", line 360, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "c:\python27\lib\json\decoder.py", line 378, in raw_decode
    raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded

对于这种类型的ValueError，如何让Python告诉您JSON文件中的错误在哪里？