What is the use of a Decorator for computed fields in a pydantic model?

In Pydantic, to create computed fields, the @property decorator or a special @pydantic.validator decorator (for validation) is used, but most often, @property allows defining a field whose value is computed dynamically based on other model fields.

This is useful when you need to obtain a value that is not stored directly but is computed upon access. For example:

from pydantic import BaseModel

class User(BaseModel):
    first_name: str
    last_name: str

    @property
    def full_name(self) -> str:
        return f"{self.first_name} {self.last_name}"

Here, full_name is a computed field that is not passed during initialization but is accessible as a model attribute. This approach helps keep the calculation logic inside the model while maintaining convenient data access.