Append to JSON file using Python
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
# Python program to update# JSONimport json # JSON data:x = '{ "organization":"GeeksForGeeks", "city":"Noida", "country":"India"}'# python object to be appendedy = {"pin":110096}# parsing JSON string:z = json.loads(x) # appending the dataz.update(y)# the result is a JSON string: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
# Python program to update# JSONimport json# function to add to JSONdef write_json(new_data, filename='data.json'): with open(filename,'r+') as file: # First we load existing data into a dict. file_data = json.load(file) # Join new_data with file_data inside emp_details file_data["emp_details"].append(new_data) # Sets file's current position at offset. file.seek(0) # convert back to json. json.dump(file_data, file, indent = 4) # python object to be appendedy = {"emp_name":"Nikhil", "email": "nikhil@geeksforgeeks.org", "job_profile": "Full Time" } write_json(y) |
Output:
Last Updated on October 25, 2021 by admin