Building Robust Object-Oriented Python Applications and Libraries/

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NamedTuple Classes

NamedTuple Classes

Learn the concept of NamedTuple classes and get to know their implementation in Python.

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Overview

Using typing.NamedTuple is somewhat similar to using @dataclass(frozen = True). There are some significant differences in the implementation details, however. In particular, the typing.NamedTuple class does not support inheritance in the most obvious way. This leads us to a design based on composition of objects in the Sample class hierarchy. With inheritance, we’re often extending a base class to add features. With composition, we’re often building multi-part objects of several different classes.

Here’s the definition of Sample as NamedTuple. It looks similar to the @dataclass definition. The definition of KnownSample, however, must change dramatically:

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class Sample(NamedTuple):
    sepal_length: float
    sepal_width: float
    petal_length: float
    petal_width: float
class KnownSample(NamedTuple):
    sample: Sample
    species: str

The ...