Strange formatting on append – JSON

recently I have been working on a project, and I needed to append a list of dictionaries to my existing JSON file. But it behaves somewhat strangely.

Here is what I have:

def write_records_to_json(json_object):
    with open("tracker.json", "r+") as f:
        json_file = json.load(f)
        json_file.append(json_object)
        print(json_file)

This is the object I’m trying to append(The object is formatted this way):

[
    {
        "file": "dnc_complaint_numbers_2021-12-03.csv",
        "date": "2021-12-03"
    }
]

And this is what I get(Pay attention to the end):
Excuse me please, for not having it more readable.

[{'file': 'dnc_complaint_numbers_2021-12-01.csv', 'date': '2021-12-01'}, {'file': 'dnc_complaint_numbers_2021-12-02.csv', 'date': '2021-12-02'}, '[\n    {\n        "file": "dnc_complaint_numbers_2021-12-03.csv",\n        "date": "2021-12-03"\n    }\n]']

Can someone tell me why is that and how to fix it? Thanks a lot.

>Solution :

From your code and output, we can infer that json_object refers to a string. This string contains JSON. json_file is not JSON, it is a list that is deserialised from JSON.

If you want to add json_object to json_file you should first deserialise the former:

json_file.extend(json.loads(json_object))

You also want to use extend instead of append here, so it is on the same level as the rest of the data.