Update existing json file in python

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The full form of JSON is JavaScript Object Notation. It means that a script (executable) file which is made of text in a programming language, is used to store and transfer the data. Python supports JSON through a built-in package called JSON. To use this feature, we import the JSON package in Python script. The text in JSON is done through quoted-string which contains the value in key-value mapping within { }. 
 

Functions Used:  

• json.loads(): json.loads() function is present in python built-in ‘json’ module. This function is used to parse the JSON string.
   

Syntax: json.loads(json_string)
Parameter: It takes JSON string as the parameter.
Return type: It returns the python dictionary object. 
 

• json.dumps(): json.dumps() function is present in python built-in ‘json’ module. This function is used to convert Python object into JSON string.
   

Syntax: json.dumps(object)
Parameter: It takes Python Object as the parameter.
Return type: It returns the JSON string. 
 

• update(): This method updates the dictionary with elements from another dictionary object or from an iterable key/value pair.
   

Syntax: dict.update([other])
Parameters: Takes another dictionary or an iterable key/value pair.
Return type: Returns None. 
 

Example 1: Updating a JSON string.
  

Python3

import json

x =  '{ "organization":"GeeksForGeeks",

        "city":"Noida",

        "country":"India"}'

y = {"pin":110096}

z = json.loads(x)

z.update(y)

print(json.dumps(z))

Output:
 

{“pin”: 110096, “organization”: “GeeksForGeeks”, “country”: “India”, “city”: “Noida”} 
 

Example 2: Updating a JSON file. Suppose the JSON file looks like this.
 

We want to add another JSON data after emp_details. Below is the implementation.

Python3

import json

def write_json(new_data, filename='data.json'):

    with open(filename,'r+') as file:

        file_data = json.load(file)

        file_data["emp_details"].append(new_data)

        file.seek(0)

        json.dump(file_data, file, indent = 4)

y = {"emp_name":"Nikhil",

     "email": "",

     "job_profile": "Full Time"

    }

write_json(y)

Output: