Jan 1, 2022
I often want to create objects that hold several related pieces of data together in the same place - like a Book object that has an author, title, etc. Python offers several methods to do this, but it's not always clear which one to use. I'll show different patterns that I use and discuss the advantages and disadvantages of each.
I call these container classes because they're mostly used to hold information.
| Name | Description |
|---|---|
| Vanilla Class | A plain Python class |
| Dictionary | A plain Python dictionary |
| Typed Dictionary | A Python dictionary plus a TypedDict schema |
| SimpleNamespace | A Python namespace object |
| NamedTuple | A tuple with names, from the collections module |
| Dataclass | A container class from the dataclasses module |
attrs Class |
The only non-standard-library solution, from the attrs library |
class Book:
"""Container class for a Book and its attributes."""
def __init__(
self,
author: str,
title: str,
publication_year: int,
isbn_10: Optional[str],
isbn_13: Optional[str],
) -> None:
self.author = author
self.title = title
self.publication_year = publication_year
self.isbn_10 = isbn_10
self.isbn_13 = isbn_13
brothers_karamazov = Book(
author="Fyodor Dostoevsky",
title="The Brothers Karamazov",
publication_year=1880,
isbn_10="0374528373",
isbn_13="978-0374528379",
)
brothers_karamazov: Book = {
"author": "Fyodor Dostoevsky",
"title": "The Brothers Karamazov",
"publication_year": 1880,
"isbn_10": "0374528373",
"isbn_13": "978-0374528379",
}
from typing import TypedDict
class Book(TypedDict):
"""Typed dictionary structure for a book object."""
author: str
title: str
publication_year: int
isbn_10: Optional[str]
isbn_13: Optional[str]
brothers_karamazov: Book = {
"author": "Fyodor Dostoevsky",
"title": "The Brothers Karamazov",
"publication_year": 1880,
"isbn_10": "0374528373",
"isbn_13": "978-0374528379",
}
from typing import NamedTuple
class Book(NamedTuple):
"""Container class for a Book and its attributes."""
author: str
title: str
publication_year: int
isbn_10: Optional[str]
isbn_13: Optional[str]
brothers_karamazov = Book(
author="Fyodor Dostoevsky",
title="The Brothers Karamazov",
publication_year=1880,
isbn_10="0374528373",
isbn_13="978-0374528379",
)
from dataclasses import dataclass
@dataclass
class Book:
"""Container class for a Book and its attributes."""
author: str
title: str
publication_year: int
isbn_10: Optional[str]
isbn_13: Optional[str]
brothers_karamazov = Book(
author="Fyodor Dostoevsky",
title="The Brothers Karamazov",
publication_year=1880,
isbn_10="0374528373",
isbn_13="978-0374528379",
)