All 15 Dataclasses & NamedTuples questions
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How do you add validation logic to a dataclass field using __post_init__? How do you use dataclasses.field(compare=False) or field(repr=False) to exclude a specific field from the auto-generated __eq__ or __repr__? How do you implement custom ordering (<, <=, >, >=) for a dataclass using order=True, and what constraint does it place on field comparison? How do you convert a dataclass instance to and from a dictionary using dataclasses.asdict() and manual reconstruction? How do you implement a custom __eq__ or __hash__ on a dataclass while still benefiting from its other auto-generated methods? How would you use dataclasses.replace() to create a modified copy of an immutable (frozen) dataclass instance? When would you choose a NamedTuple over a @dataclass, and vice versa, given their overlapping use cases? How would you use Python 3.10+'s kw_only=True (or per-field kw_only) to require dataclass fields be passed as keyword arguments only?
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How would you implement inheritance between dataclasses, and what field-ordering rule must be respected across the hierarchy?

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Answer

A dataclass CAN inherit from another dataclass; the subclass's own fields are appended AFTER the parent's fields in the generated __init__ signature — meaning if the parent has any field WITH a default, every field the subclass adds must ALSO have a default, or you'll hit the same 'non-default argument follows default argument' error.
@dataclass
class Animal:
    name: str
    sound: str = "..."

@dataclass
class Dog(Animal):
    breed: str = "unknown"  # must have a default, since parent's 'sound' already has one

d = Dog(name="Rex", breed="Labrador")
print(d)  # Dog(name='Rex', sound='...', breed='Labrador')
Real-world example Building a hierarchy of related dataclasses (like a base Event class extended by specific event types) sharing common fields.

Common follow-ups: How does Python 3.10+'s kw_only=True parameter help avoid this field-ordering restriction entirely?

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All 15 Dataclasses & NamedTuples questions