Python and JSON: Complete Guide to json Module

The Python json Module

Python's built-in json module makes working with JSON data simple and efficient.

Parsing JSON

json.loads() - Parse JSON String

import json

json_string = '{"name": "Alice", "age": 30}'
data = json.loads(json_string)

print(data['name'])  # "Alice"
print(type(data))    # <class 'dict'>

json.load() - Read from File

import json

with open('data.json', 'r') as file:
    data = json.load(file)
    print(data)

Generating JSON

json.dumps() - Convert to JSON String

import json

data = {
    "name": "Bob",
    "age": 25,
    "active": True
}

json_string = json.dumps(data)
print(json_string)
# {"name": "Bob", "age": 25, "active": true}

Pretty Printing

json_string = json.dumps(data, indent=2)
print(json_string)
# {
#   "name": "Bob",
#   "age": 25,
#   "active": true
# }

json.dump() - Write to File

with open('output.json', 'w') as file:
    json.dump(data, file, indent=2)

Type Mapping

| Python | JSON |

|--------|------|

| dict | object |

| list, tuple | array |

| str | string |

| int, float | number |

| True | true |

| False | false |

| None | null |

Common Options

Sort Keys

json.dumps(data, sort_keys=True)

Handle Non-Serializable Objects

from datetime import datetime

def json_serial(obj):
    if isinstance(obj, datetime):
        return obj.isoformat()
    raise TypeError(f"Type {type(obj)} not serializable")

data = {"timestamp": datetime.now()}
json.dumps(data, default=json_serial)

Error Handling

try:
    data = json.loads(invalid_json)
except json.JSONDecodeError as e:
    print(f"Error: {e}")
    print(f"Line {e.lineno}, Column {e.colno}")

Working with APIs

import requests
import json

response = requests.get('https://api.example.com/users')
data = response.json()  # Automatically parses JSON

for user in data['users']:
    print(user['name'])

Best Practices

Always use with statement for file operations

Handle JSONDecodeError exceptions

Use indent for readable output

Validate data before parsing

Use UTF-8 encoding for files

Conclusion

Python's json module is powerful and easy to use. Master json.loads(), json.dumps(), and file operations for all your JSON needs!