Python Typing

obj.attribute vs obj["member_of_collection"]

Property vs attribute

• property is a special kind of attribute
  • has either a __get__, __set__ or __delete__
  • spam.eggs will return the result of __get__

spam = SomeObject()
print(spam.eggs)

TypedDict

• new in Python 3.8
• https://adamj.eu/tech/2021/05/10/python-type-hints-how-to-use-typeddict/

from typing import TypedDict


class SalesSummary(TypedDict):
    sales: int
    year: NotRequired[int]
    product_codes: list[str]

def get_sales_summary() -> SalesSummary:
    pass

Circular Dependencies with types

from __future__ import annotations
from typing import TYPE_CHECKING # false at runtime

if TYPE_CHECKING:
    from module_b import B

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Last update: 2023-04-24