Python DataclassesPython 데이터클래스

from dataclasses import dataclass, field
from typing import List

@dataclass
class Point:
    x: float
    y: float
    z: float = 0.0  # 기본값

p = Point(1.0, 2.0)
print(p)         # Point(x=1.0, y=2.0, z=0.0)
print(p == Point(1.0, 2.0))  # True (자동 __eq__)

@dataclass
class Inventory:
    name: str
    items: List[str] = field(default_factory=list)  # 가변 기본값
    _internal: int = field(default=0, repr=False, compare=False)

    # post_init으로 검증
    def __post_init__(self):
        if not self.name:
            raise ValueError("이름은 필수입니다")

# frozen=True: 불변 (hashable)
@dataclass(frozen=True)
class Color:
    r: int; g: int; b: int

c = Color(255, 0, 0)
# c.r = 100  # FrozenInstanceError

# order=True: <, <=, >, >= 자동 구현
@dataclass(order=True)
class Version:
    sort_index: int = field(init=False, repr=False)
    major: int
    minor: int
    patch: int

    def __post_init__(self):
        self.sort_index = self.major * 10000 + self.minor * 100 + self.patch

# slots=True (Python 3.10+): __slots__ 자동 생성
@dataclass(slots=True)
class FastPoint:
    x: float
    y: float