What are dataclasses?

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**`@dataclass`** (from `dataclasses`, 3.7+) auto-generates the boilerplate for classes that mostly hold data. From typed class-level fields it writes `__init__`, `__repr__`, and `__eq__` for you (and more on request), so a clear, correct value object is a few lines.

Useful options:

- **`frozen=True`** — immutable instances (and makes them hashable), great for value objects / dict keys.
- **`order=True`** — generates `<`, `<=`, etc. for sorting.
- **`slots=True`** (3.10+) — generate `__slots__` for memory savings.
- **`field(default_factory=list)`** — the correct way to give a mutable default (avoids the shared-default bug).
- `kw_only`, `__post_init__` (extra validation/derived fields).

Compared to alternatives: less magic than a hand-written class, more structure than a dict/tuple, and standard-library (no dependency) unlike `attrs`; `NamedTuple` is similar but always immutable and tuple-like.

**Interview tip:** 'removes `__init__`/`__repr__`/`__eq__` boilerplate from data-holding

What are dataclasses?

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