Python JSON Handling | Learn Computer Academy

Working with JSON

JSON is the standard format for exchanging data — an API response, a config file, data saved between program runs. Python's built-in json module handles converting between it and Python's own dicts and lists.

Python to JSON — json.dumps()

import json

user = {'name': 'Sam', 'age': 28, 'active': True}
json_string = json.dumps(user)
print(json_string)
# {"name": "Sam", "age": 28, "active": true}

Pretty-Printing for Readability

print(json.dumps(user, indent=2))

JSON to Python — json.loads()

json_string = '{"name": "Sam", "age": 28}'
user = json.loads(json_string)
print(user['name'])   # Sam — a regular Python dict now

Reading and Writing JSON Files

# Writing
with open('user.json', 'w') as f:
    json.dump(user, f, indent=2)

# Reading
with open('user.json') as f:
    user = json.load(f)

dump()/load() (no "s") work directly with an open file; dumps()/loads() (with an "s", for "string") work with a Python string already in memory.

Python Types vs. JSON Types

Python	JSON
dict	object
list, tuple	array
str	string
int, float	number
True / False	true / false
None	null

Handling Invalid JSON

try:
    data = json.loads('{invalid json}')
except json.JSONDecodeError as e:
    print(f'Invalid JSON: {e}')

A one-way conversion for tuples

A tuple converts to a JSON array and comes back as a Python list, not a tuple — JSON has no tuple type of its own, so that distinction is lost in the round trip.