Python sub Dataclass identify inherited attributes

Question

I have 2 dataclass like below:

from dataclasses import dataclass

@dataclass
class Line:
    x: int
    length: int
    color: str

@dataclass
class Rectangle(Line):
    y: int
    height: int
    fill: bool

    def get_dict(self):
        """ return only y, height, and fill """

If I construct a Rectangle object, is it possible to identify which attributes are inherited from the parent data class?

For example, how can I implement the get_dict() method in Rectangle without explicitly typing out all the variables and their values?

Answer 1

Note that dataclasses has an asdict helper function which can be used to serialize a dataclass to a dict object; however, that also includes fields from a superclass like Line for example, so that's probably not what you want here.

I'd suggest looking into other attributes like Rectangle.__annotations__ which should only have a list of dataclass fields which are exclusive to the class Rectangle. For example:

from dataclasses import dataclass, asdict
from typing import Any


@dataclass
class Line:
    x: int
    length: int
    color: str


@dataclass
class Rectangle(Line):
    y: int
    height: int
    fill: bool

    def get_dict(self) -> dict[str, Any]:
        """ return only y, height, and fill """
        return {f: getattr(self, f) for f in self.__annotations__}
        # return asdict(self)


print(Rectangle(1, 2, 3, 4, 5, 6).get_dict())

Should only return the fields that are exclusive to Rectangle:

{'y': 4, 'height': 5, 'fill': 6}