json (web, native) – Edge Python

json is loads and dumps. Import it by bare name, both runtimes resolve it with no manifest. To pin a different version, import it by URL or through a packages.json alias, see Modules.

loads accepts the object_hook, object_pairs_hook, parse_float, parse_int, and parse_constant callables. dumps accepts indent, sort_keys, ensure_ascii, check_circular, allow_nan, skipkeys, default, separators, and cls. Parse failures raise ValueError, and a non-serializable value raises TypeError unless default handles it. Integers cross as 128-bit values, so loads accepts numbers beyond 64 bits. Non-finite floats map to NaN, Infinity, and -Infinity on both sides, and integer-valued floats dump with a trailing .0 so a round-trip preserves the type.

from json import dumps, loads data = loads('{"name":"ada","tags":["math","cs"]}') print(data["name"]) print(dumps({"k": [1, 2, 3], "ok": True}))

Output · expected


ada
{"k":[1,2,3],"ok":true}

indent and sort_keys shape the output:

from json import dumps print(dumps({"b": 1, "a": [True, None]}, indent=2, sort_keys=True))

Output · expected


{
  "a": [
    true,
    null
  ],
  "b": 1
}

A round-trip preserves types, even past 64 bits:

from json import dumps, loads big = 2 ** 100 print(loads(dumps(big)) == big) print(dumps(3.0)) print(loads(dumps(3.0)))

Output · expected


True
3.0
3.0

Failures raise ordinary exceptions you can catch:

from json import dumps, loads try: loads("{nope") except ValueError as e: print("parse failed:", e) def helper(): pass try: dumps({"fn": helper}) except TypeError as e: print("dump failed:", e)

Output · expected


parse failed: unknown literal at byte 1
dump failed: 'function' is not JSON-serializable