Question

By definition the JSON string is wrapped with double quote.

In fact:

json.loads('{"v":1}') #works

json.loads("{'v':1}") #doesn't work

But how to deal with the second statements?
I’m looking for a solution different from eval or replace.
Thanks.

Answer 1

Not sure if I got your requirements right, but are you looking for something like this?

def fix_json(string_):
    if string_[0] == string_[-1] == "'":
        return '"' + string_[1:-1] +'"'
    return string_

Example usage:

>>> fix_json("'{'key':'val\"'...cd'}'")
"{'key':'val"'...cd'}"

EDIT: it seems that the humour I tried to have in making the example above is not self-explanatory. So, here’s another example:

>>> fix_json("'This string has - I'm sure -  single quotes delimiters.'")
"This string has - I'm sure -  single quotes delimiters."

This examples show how the “replacement” only happens at the extremities of the string, not within it.

you could also achieve the same with a regular expression, of course, but if you are just checking the starting and finishing char of a string, I find using regular string indexes more readable….