json — JSON encoder / decoder

import json

Convert between Python objects and JSON strings. Full RFC 8259.

Decoding

json.loads(s) — string → Python object

json.loads('{"name": "Dave", "age": 42}')
# {'name': 'Dave', 'age': 42}

json.loads('[1, 2, 3]')          # [1, 2, 3]
json.loads('null')               # None
json.loads('true')               # True
json.loads('3.14')               # 3.14

json.load(file) — file → Python object

with open('CONFIG.JSO', 'r') as f:
    cfg = json.load(f)

⚠️ DOS uses 8.3 names. .JSON is 4-char extension and gets truncated to .JSO on FAT. Save your JSON with .JSO, .JSN, or .CFG to avoid surprises.

Encoding

json.dumps(obj, separators=None) — Python → string

json.dumps({'name': 'Dave', 'age': 42})
# '{"name": "Dave", "age": 42}'

json.dumps([1, 2, 3])            # '[1, 2, 3]'
json.dumps([1, 2, 3], separators=(',', ':'))  # '[1,2,3]'  (no spaces)

json.dump(obj, file) — Python → file

with open('OUT.JSO', 'w') as f:
    json.dump({'ok': True}, f)

Type mapping

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

Round-trip preserves types except tuple → list. No custom encoders / decoders (no default= or object_hook= parameters).

Example: config file pattern

import json

DEFAULTS = {'ssh_user': 'root', 'ssh_port': 22, 'timeout': 30}

try:
    with open('CONFIG.JSO', 'r') as f:
        config = {**DEFAULTS, **json.load(f)}
except OSError:
    config = DEFAULTS.copy()

print('using user:', config['ssh_user'])

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Credit: MicroPython json docs (MIT).