Transforming JSON keys and values

Question

I have a simple json in python that looks like :

{
    "list": [{
            "key1": "value1"
        },
        {
            "key1": "value1"
        }
    ]
}

I want to transform this to the following json. Any suggestions how I can do it with python without installing additional libraries?

{
    "list": [{
        "keys": {
            "name": "key1",
            "value": "value1"
        }
    }, {
        "keys": {
            "name": "key1",
            "value": "value1"
        }
    }]
}

Answer 1

Not sure from your question if you already have the json read into a variable, or if it is in a file. This is assuming you have it in a variable already:

in_json = {
    "list": [{
            "key1": "value1"
        },
        {
            "key2": "value2"
        }
    ]
}

out_json = {"list":[]}
for kd in in_json["list"]:
    sub_kd = {"keys": {}}
    for k,v in kd.iteritems():
        sub_kd["keys"]["name"] = k
        sub_kd["keys"]["value"] = v

    out_json["list"].append(sub_kd)

print(out_json)

It just loops through the json making dictionaries to append to the out_json dictionary. You could make this print pretty with the json library and also save to file with it

Answer 2

You didn't indicate exactly what contains the JSON data is in, so I've put it all in a string in the example code below and uses the json.loads() function to turn it into a Python dictionary. If it's in a file, you can use the module's json.load() function instead.

It also make the assume that each sub-JSON object in the "list" list consists of only one key/value pair as shown in your question.

The code below changes the deserialized dictionary in-place and pretty-prints the result of doing that by using the json.dumps() function to reserialize it.

Note that I changed the keys and values in sample input JSON slightly to make it easier to see the correspondence between it and the printed results.

import json


json_in = '''
    {
        "list": [
            {
                "key1": "value1"
            },
            {
                "key2": "value2"
            }
        ]
    }
'''

json_data = json.loads(json_in)  # Deserialize.

for i, obj in enumerate(json_data['list']):
    # Assumes each object in list contains only one key, value pair.
    newobj = { 'name': next(iter(obj.keys())),
              'value': next(iter(obj.values()))}
    json_data['list'][i] = {'keys': newobj}

print(json.dumps(json_data, indent=4))  # Reserialize and print.

Printed result:

{
    "list": [
        {
            "keys": {
                "name": "key1",
                "value": "value1"
            }
        },
        {
            "keys": {
                "name": "key2",
                "value": "value2"
            }
        }
    ]
}