Python 类型提示填充了 myclass 对象的双端队列 [英] Python type hinting a deque filled with myclass objects

问题描述

使用 Python 3.6 或更新版本，我想键入一个函数 myfunc 来返回 MyClass 的对象.

我如何暗示 myqueue 是一个充满 MyClass 对象的 deque?

from collections import dequeglobal_queue = deque()类我的类:经过def myfunc(myqueue=global_queue) ->我的课:返回 myqueue.popleft()对于范围内的我(10):global_queue.append(MyClass())

解决方案

在 Python 3.9 中，您可以直接使用 deque['MyClass']().

如果您使用的是 Python 3.6.1 或更高版本，您可以使用 typing.Deque:

from 输入 import Deque从集合导入双端队列global_queue: Deque['MyClass'] = deque()类我的类:经过def myfunc(myqueue: Deque[MyClass] = global_queue) ->我的课:返回 myqueue.popleft()对于范围内的我(10):global_queue.append(MyClass())

或者，您可以改为执行 global_queue = Deque['MyClass']() —— 在运行时，这将构造一个 collections.deque 对象.>

如果您需要支持 Python 3.5，请安装 typing_extensions 3rd 方库并执行 from typing_extensions import Deque.该库包含类型的向后移植，这些类型是在将 Typing 模块首次添加到标准库之后添加的.

using Python 3.6 or newer, I want to type hint a function myfunc that returns an object of MyClass.

How can I hint, that myqueue is a deque filled with MyClass objects?

from collections import deque

global_queue = deque()

class MyClass:
    pass

def myfunc(myqueue=global_queue) -> MyClass:
    return myqueue.popleft()

for i in range(10):
    global_queue.append(MyClass())

解决方案

In Python 3.9, you can use deque['MyClass']() directly.

If you are using Python 3.6.1 or higher, you can use typing.Deque:

from typing import Deque
from collections import deque

global_queue: Deque['MyClass'] = deque()

class MyClass:
    pass

def myfunc(myqueue: Deque[MyClass] = global_queue) -> MyClass:
    return myqueue.popleft()

for i in range(10):
    global_queue.append(MyClass())

Alternatively, you can do global_queue = Deque['MyClass']() instead -- at runtime, that'll construct a collections.deque object.

If you need to support Python 3.5, install the typing_extensions 3rd party library and do from typing_extensions import Deque. That library contains backports of types that were added after the typing module was first added to the standard library.

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