具有已知键类型的 Python 3 字典 [英] Python 3 dictionary with known keys typing

问题描述

我正在使用 Python 3 打字功能以实现更好的自动完成.

I'm using Python 3 typing feature for better autocomplete.

很多时候我有返回键/值(字典)和特定键的函数.超级简单的例子:

Many times I have functions that return key/value (dictionary) with specific keys. super simple example:

def get_info(name):
    name_first_letter = name[0]
    return {'my_name': name, 'first_letter': name_first_letter}

我想给这个函数添加类型提示，告诉其他使用这个函数的人期待什么.

I want to add type hinting to this function to tell others who use this function what to expect.

我可以这样做:

 class NameInfo(object):
     def __init__(self, name, first_letter):
         self.name = name
         self.first_letter = first_letter

然后将函数签名改为:

def get_info(name) -> NameInfo:

但是每个字典需要太多的代码.

But it requires too much code for each dictionary.

在这种情况下，最佳做法是什么?

What is the best practice in that case?

推荐答案

正如 Blckknght 所指出的，你和 Stanislav Ivanov 在评论中，你可以使用 NamedTuple:

As pointed out by Blckknght, you and Stanislav Ivanov in the comments, you can use NamedTuple:

from typing import NamedTuple


class NameInfo(NamedTuple):
    name: str
    first_letter: str


def get_info(name: str) -> NameInfo:
    return NameInfo(name=name, first_letter=name[0])

从 Python 3.8 开始，您可以使用 TypedDict 与您想要的更相似:

Starting from Python 3.8 you can use TypedDict which is more similar to what you want:

from typing import TypedDict


class NameInfo(TypedDict):
    name: str
    first_letter: str


def get_info(name: str) -> NameInfo:
    return {'name': name, 'first_letter': name[0]}

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