Convert a string with the name of a variable to a dictionary

Question

I have a string which is little complex in that, it has some objects embedded as values. I need to convert them to proper dict or json.

foo = '{"Source": "my source", "Input": {"User_id": 18, "some_object": this_is_a_variable_actually}}'

Notice that the last key some_object has a value which is neither a string nor an int. Hence when I do a json.loads or ast.literal_eval, I am getting malformed string errors, and so Converting a String to Dictionary doesn't work.

I have no control over the source of the string.

Is it possible to convert such strings to dictionary

The result I need is a dict like this

dict = {
        "Source" : "Good",
        "object1": variable1,
        "object2": variable2
}

The thing here is I wouldn't know what is variable1 or 2. There is no pattern here.

One point I want to mention here is that, If I can make the variables as just plain strings, that is also fine

For example,

dict = {
        "Source" : "Good",
        "object1": "variable1",
        "object2": "variable2"
}

This will be good for my purpose. Thanks for all the answers.

If this were possible, how would it even know how to evaluate `this_is_a_variable_actually` and replace with that variable value? — OneCricketeer, Jul 17 '16 at 11:08
I agree, but my trouble is I don't know if this would be this_is_a_variable_actually or i_dont_know_what_will_come_here. If would have known what is expected, I would do a string replace and finish it off. — Prabhakar Shanmugam, Jul 17 '16 at 11:10
Yeah, what do you want to get as a result? Provide some examples. — Leonid Shvechikov, Jul 17 '16 at 11:14
You could `eval` it in a context that includes a definition of `this_is_a_variable_actually`, but how have you ended up with this string in the first place? — jonrsharpe, Jul 17 '16 at 11:14
I think it may be helpful http://stackoverflow.com/questions/988228/converting-a-string-to-dictionary — Dudnikof, Jul 17 '16 at 11:15
Along with previous comment. The data source should know nothing about variables in your current python context. — OneCricketeer, Jul 17 '16 at 11:15
The structure of the dict is constant? you always want to evaluate the "some object" variable? — Ohad Eytan, Jul 17 '16 at 11:21
Check @Martijn answer : http://stackoverflow.com/questions/25867475/ast-literal-eval-for-variables-in-python — dsgdfg, Jul 17 '16 at 11:27
I checked the solution provided. There they start off with a proper dictionary. Mine is a string with keys as strings and values as some random variables. As I requested in my question, it is ok, if I can stringify the value also. That will solve the problem for now. — Prabhakar Shanmugam, Jul 17 '16 at 11:41

score 2 · Answer 1 · answered Jul 17 '16 at 13:47

It's a bit of a kludge using the demjson module which allows you to parse most of a somewhat non-confirming JSON syntax string and lists the errors... You can then use that to replace the invalid tokens found and put quotes around it just so it parses correctly, eg:

import demjson
import re

foo = '{"Source": "my source", "Input": {"User_id": 18, "some_object": this_is_a_variable_actually}}'

def f(json_str):
    res = demjson.decode(json_str, strict=False, return_errors=True)
    if not res.errors:
        return res
    for err in res.errors:
        var = err.args[1]
        json_str = re.sub(r'\b{}\b'.format(var), '"{}"'.format(var), json_str)
    return demjson.decode(json_str, strict=False)

res = f(foo)

Gives you:

{'Input': {'User_id': 18, 'some_object': 'this_is_a_variable_actually'}, 'Source': 'my source'}

Note that while this should work in the example data presented, your mileage may vary if there's other nuisances in your input that require further munging.

Convert a string with the name of a variable to a dictionary

1 Answers1