How do you add variables and update values to existing JSON dictionaries?

Question

I want to export certain variables to an existing JSON file, but I don't know how to add something to an existing dictionary, I also have dictionaries that already have the variables but I want to update their values, how do I do this?

The python code that I have now makes a new dictionary, which is not what I want, any help is appreciated

Python file:

export_dict = {'salary':salary_int,'interest':interest_int}

with open(f'{os.getcwd()}/Data/Insta-database.json','r') as inputfile:
    file = json.load(inputfile)
    file['data'].append(export_dict)

with open(f'{os.getcwd()}/Data/Insta-database.json', 'w') as outfile: 
    json.dump(file, outfile, indent = 4)

JSON file:

{
    "data": [
        {
            "name": "quesa",
            "surname": "fum", // I want to add the salary and interest variables beneath these
        },
        {
            "name": "hau",
            "surname": "guygo",
            "salary": "213,324", // I want to update these values
            "interest": "5%", // I want to update these values
        },
        {
            "name": "ksmair",
            "surname": "bree",
            "salary": "943,229", // I want to update these values
            "interest": "15%", // I want to update these values
        }
    ]
}

I think you are using either to work python3 or python2 cuz you have used both tags, answers should be in both, do you want answer in both python2 and python3? — imxitiz, Aug 01 '21 at 11:26
I removed both tags. In this day and age, expect everyone to have moved on to Python 3. Unless you are *specifically* asking about how to solve a cross-version compatibility problem (in which case your question should obviously describe that problem) you should not mix the [tag:python-2.7] and [tag:python-3.x] tags. — tripleee, Aug 01 '21 at 12:19

tripleee · Accepted Answer · 2021-08-01T13:11:38.827

Like you discovered yourself, your code adds a new key to the top-level dictionary. If there are multiple places where you want to update the values, you need to modify each of them separately, perhaps via a loop.

with open('Data/Insta-database.json', 'r') as inputfile:
    file = json.load(inputfile)

for elem in file['data']:
    elem.update(export_dict)

with open('Data/Insta-database.json', 'w') as outfile: 
    json.dump(file, outfile, indent = 4)

Demo: https://ideone.com/yUKnrJ

Notice also how the os.getcwd() call is not necessary; the operating system by definition resolves relative file names from the current working directory. For details, see What exactly is current working directory?

How do you add variables and update values to existing JSON dictionaries?

1 Answers1