Python JSON Tutorial: Load, Save, and Convert

From String

import json
text = '{"name": "Ming", "age": 17}'
data = json.loads(text)     # string → dict
back = json.dumps(data)     # dict → string

From File

with open("config.json") as f:
    data = json.load(f)

with open("config.json", "w") as f:
    json.dump(data, f, indent=2, ensure_ascii=False)

Pretty Printing

print(json.dumps(data, indent=2, sort_keys=True))

Gotchas

• JSON keys are always strings. Python dict keys become strings when dumped.
• JSON has no tuples — they become lists when loaded.
• Use ensure_ascii=False to keep Chinese characters readable.

Custom Objects

class User:
    def __init__(self, name): self.name = name

u = User("Ming")
json.dumps(u.__dict__)   # {"name": "Ming"}