45  JSON

Basic Operations in the json Module

1. Serialization: Converting a Python object (e.g., dictionary, list, etc.) into a JSON string.
2. Deserialization: Converting a JSON string into a Python object (e.g., dictionary, list, etc.).

import json

45.1 Serialization (Convert Python -> JSON)

45.1.1 json.dumps()

This function is used to convert (serialize) a Python object into a JSON-formatted string.

import json

# Python dictionary
person = {
    "name": "Alice",
    "age": 30,
    "city": "New York",
    "is_employee": True
}

# Convert Python object to JSON string
json_string = json.dumps(person)
print(json_string)

{"name": "Alice", "age": 30, "city": "New York", "is_employee": true}

• dumps() converts the Python object to a JSON string.
• Python data types like dict, list, int, str, and bool are automatically converted to corresponding JSON types.
  • True becomes true (in JSON format).
  • Strings are enclosed in double quotes in JSON.

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To save the JSON string to a file, use the json.dump() function. This function writes the JSON representation directly to a file.

with open('person.json', 'w') as file:
    json.dump(person, file)

45.2 Deserialization (JSON -> Python Object)

45.2.1 json.loads()

This function is used to parse (deserialize) a JSON-formatted string into a Python object.

import json

# JSON string
json_string = '{"name": "Alice", "age": 30, "city": "New York", "is_employee": true}'

# Convert JSON string to Python object (dictionary)
person_dict = json.loads(json_string)
print(person_dict)

{'name': 'Alice', 'age': 30, 'city': 'New York', 'is_employee': True}

• loads() converts a JSON string to a corresponding Python object.
  • true in JSON becomes True in Python.
  • JSON strings are converted to Python dictionaries.

To read JSON data from a file and convert it into a Python object, use the json.load() function.

with open('person.json', 'r') as file:
    person_dict = json.load(file)

print(person_dict)

45.2.2 Summary:

• json.dumps() converts a Python object to a JSON string.
• json.loads() converts a JSON string back to a Python object.
• json.dump() writes a Python object as JSON data to a file.
• json.load() reads JSON data from a file and converts it back to a Python object.

The json module makes it easy to work with JSON data, whether you are reading from or writing to files, or converting between Python objects and JSON strings.