Convert bool values to string in json.dumps()

Question

I'm trying to convert a python dict into json, however the API I'm accessing doesn't take bool value instead it uses "true"/"false" string.

Example:

dct = { "is_open": True }
json.dumps(dct)

currently gives a bool output: { "is_open": true }

but what I want is lower-case string output: { "is_open": "true" }

I tried json.dumps(dct, cls=MyEncoder) but it doesn't work, only non-native object get passed to MyEncoder default.

class MyEncoder(json.JSONEncoder):
        def default(self, o):
            if isinstance(o, bool):
                return str(o).lower()
            return super(MyEncoder, self).default(o)

Any help would be great.

(Btw this is not my API I'm accessing, so I can't modify the API to access true false value instead of the string alternative.)

Answer 1

If it were me, I'd convert the Python data structure to the required format and then call json.dumps() :

import json
import sys

def convert(obj):
    if isinstance(obj, bool):
        return str(obj).lower()
    if isinstance(obj, (list, tuple)):
        return [convert(item) for item in obj]
    if isinstance(obj, dict):
        return {convert(key):convert(value) for key, value in obj.items()}
    return obj

dct = {
  "is_open": True
}
print (json.dumps(dct))
print (json.dumps(convert(dct)))

Output:

{"is_open": true}
{"is_open": "true"}

Answer 2

You can use the following one-liner:

{k:str(v).lower() for k,v in d.items()}

Output:

{'a': 'false', 'b': 'true'}