204 – Reading and writing JSON

You can use the module json to read and write data in the JSON format, which is very suitable to represent the most common Python built-in types like lists and dictionaries, strings, integers and floats, and Boolean values.

To write data in the JSON format to a file, use the function json.dump:

import json

data = {
  "name": "Rodrigo",
  "newsletters": 2,
}

with open("data.json", "w") as f:
    json.dump(data, f)

The call to json.dump writes a file that looks like this:

{"name": "Rodrigo", "newsletters": 2}

You can retrieve the data and convert it back to the appopriate Python types with json.load:

import json

with open("data.json", "r") as f:
    data = json.load(f)
    
print(data)

data = {
  "name": "Rodrigo",
  "newsletters": 2,
}