python – json , how to make a json flat

so i have a nested json that contains two groups , each group has a field that contains more sub groups i would like to pop all the sub groups out to flatten the json and remove the sub groups field

What is the correct way to do it

JSON :

[
    {
        "groupId": "a_group",
        "version": "2.0.1",
        "type": "jar",
        "sub_group": [
            {
                "groupId": "a_1",
                "version": "2.0.0",
                "type": "jar",
                "sub_group": []
            },
            {
                "groupId": "a_2",
                "version": "2.0.1",
                "type": "jar",
                "sub_group": [
                                {
                                "groupId": "a_1",
                                "version": "2.0.0",
                                "type": "jar",
                                "sub_group": []
                                },
                ],
            }
        ],
    },
    {
        "groupId": "c_group",
        "version": "1.9.1",
        "type": "jar",
        "sub_group": [
                    {
                "groupId": "a_1",
                "version": "2.0.0",
                "type": "jar",
                "sub_group": []
            },
        ],
    },
}

This is the expected result: I need to pop all the sub groups and make them appear as a flat json like this

[{
        "groupId": "a_group",
        "version": "2.0.1",
        "type": "jar",
        "sub_group": []
    },
    {
        "groupId": "a_1",
        "version": "2.0.0",
        "type": "txt",
        "sub_group": []
    },
    {
        "groupId": "a_2",
        "version": "2.0.1",
        "type": "jar",
        "sub_group": []
    },
    {
        "groupId": "c_group",
        "version": "1.9.1",
        "type": "jar",
        "sub_group": []
    },
]

Answer

Well , i had an interview question very similar to your question

This is my answer:

def flatten_json(self,json_data) ->json:
    '''
    :param json_data: The json file to work on
    :return: A json
    '''

    out = []
    def flatten(key):
        if isinstance(key, dict):
            if key['sub_group']:
                flatten(key['sub_group'])
                key['sub_group'] = []
                out.append(key)
            else:
                out.append(key)

        # in case we have multiple items in the list[]
        elif isinstance(key, list):
            for val in key:
                flatten(val)

    flatten(json_data)
    return json.dumps(out)

This is not the nicest solution but it works pretty good I took the liberty of assuming the name of the sub_group is always subgroup I used a recursion and i am handling moving into the dictionaries with the isinstance method to check if i am looking at a dictionary , if not then it means i have a list containing something else I handle that in the elif part and i iterate over each item in the list