Breaching outside of Python 101 books and guides, you might’ve stumbled across data classes that look something like this:
from dataclasses import dataclass
@dataclass
class User:
name: str
age: intWhat is a data class?
A data class is a Python decorator that allows us to write code that generates common special (“dunder”) methods for a class based on its type-annotated fields. You define the data structure using type annotations and the @dataclass decorator uses that structure to create your class.
» Dunder (“double underscore”) methods are special methods that are intended to be used internally to the class like object construction (__init__), comparison (__eq__, __lt__, __gt__, etc.), and more.
In short, these classes allow you to write less boilerplate code and communicate clearer intent of the class.
Why would we use a data class?
Let’s take a scenario where you’re writing a class to hold weather observations. You might write it like this:
class WeatherObservation:
def __init__(
self,
temperature: float,
dewpoint: float,
wind_speed: float,
wind_direction: int
):
self.temperature = temperature
self.dewpoint = dewpoint
self.wind_speed = wind_speed
self.wind_direction = wind_direction