Dataclasses for records

@dataclass generates common record methods such as __init__ and __repr__. Type annotations describe intended fields but do not validate values at runtime.

Worked example

from dataclasses import dataclass

@dataclass
class Session:
    subject: str
    minutes: int

item = Session("Python", 25)
print(item.subject, item.minutes)
print(item)

Python 25
Session(subject='Python', minutes=25)

Why this works

The decorator builds methods using annotated fields in their declared order. Runtime validation still needs explicit code when required.

Another case

from dataclasses import dataclass, field
@dataclass
class Plan:
    sessions: list[int] = field(default_factory=list)
a = Plan()
b = Plan()
a.sessions.append(20)
print(a.sessions, b.sessions)

[20] []

Practice

Add a day: int field and construct Session("Python", 25, 1).

Try another case

Is Session("Python", 25) == Session("Python", 25) True or False?