pocketpy/docs/modules/dataclasses.md

---

icon: package

label: dataclasses

dataclasses

@dataclass uses annotated fields to supply __init__, __repr__, __eq__, and __ne__ when the class does not define them.

from dataclasses import dataclass, asdict

@dataclass
class Player:
    name: str
    score: int = 0

player = Player('Ada', score=10)
assert player == Player('Ada', 10)
assert asdict(player) == {'name': 'Ada', 'score': 10}
assert repr(player) == "Player(name='Ada', score=10)"

Fields without defaults must precede fields with defaults. Base-class annotations are included. Annotations describe fields; they do not validate the values assigned to them.

Differences from CPython

• Use @dataclass directly. Decorator options such as frozen, order, slots, and kw_only are not implemented.
• There is no field(), default_factory, or automatic __post_init__() call.
• A mutable class-level default is shared. Create per-instance containers in your own __init__ instead.
• asdict(obj) produces a shallow field dictionary. Nested objects and containers are not recursively converted or copied.

Implementation: dataclasses.py.