How do I write JSON data to a file in Python?

General Discussions
1

I have JSON data stored in a dictionary, and I want to write it to a file. I tried the following approach:

f = open('data.json', 'wb')
f.write(data)

However, this results in the error:

TypeError: must be string or buffer, not dict

How can I correctly save the JSON data to a file in Python?

2

To write a Python dictionary to a JSON file, you need to first encode the dictionary as JSON before writing. Here’s the recommended approach for maximum compatibility (both Python 2 and 3):

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

For modern systems using Python 3 and UTF-8 support, you can use the following method to ensure better formatting:
import json
with open('data.json', 'w', encoding='utf-8') as f:
    json.dump(data, f, ensure_ascii=False, indent=4)

You can refer to the JSON documentation for more details on encoding options.

3

If you want to write the JSON string directly, you can use json.dumps to convert the dictionary to a JSON-formatted string before writing it to the file:

import json
with open('data.json', 'w') as f:
    f.write(json.dumps(data, ensure_ascii=False, indent=4))
4

If you prefer to use pathlib for better path handling:

from pathlib import Path
import json
path = Path('data.json')
with path.open('w', encoding='utf-8') as f:
    json.dump(data, f, ensure_ascii=False, indent=4)