How to Convert a key-value array dictionary to key-value JSON

Depending on the API, sometimes we need to change the structure of the dictionary before we convert it to JSON. For example, assume that we have the following dictionary.

my_dict = {'variant_id' : [1,2,3],
           'impressions' : [100, 120, 90]}
my_dict           

Output:

{'variant_id': [1, 2, 3], 'impressions': [100, 120, 90]}

Let’s say that we want to generate a JSON file of the following form:

[{'variant_id': 1, 'impressions': 100},
 {'variant_id': 2, 'impressions': 120},
 {'variant_id': 3, 'impressions': 90}]

We can generate this file as follows:

import json
my_json = [{"variant_id":int(i), "impressions":j} for i,j in zip(my_dict['variant_id'],my_dict['impressions'])]     
my_json = json.dumps(my_json)  
my_json 

Output:

'[{"variant_id": 1, "impressions": 100}, {"variant_id": 2, "impressions": 120}, {"variant_id": 3, "impressions": 90}]'

Finally, if we want to convert the JSON to Pandas data frame:

import pandas as pd

pd.json_normalize(json.loads(my_json))