Python

Question

让我们考虑文档中的以下示例：

import asyncio

async def factorial(name, number):
    f = 1
    for i in range(2, number+1):
        print("Task %s: Compute factorial(%s)..." % (name, i))
        await asyncio.sleep(1)
        f *= i
    print("Task %s: factorial(%s) = %s" % (name, number, f))

loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.gather(
    factorial("A", 2),
    factorial("B", 3),
    factorial("C", 4),
))
loop.close()

收集函数在模块中是这样呈现的：

asyncio.gather(*coros_or_futures, loop=None, return_exceptions=False)

一切正常，但对于我的现实生活问题，我需要传入收集函数，而不是传递具有硬编码参数的多个函数，而是对创建多个函数的某种形式的元组理解。

我试过了：

loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.gather(
    [factorial(str(g),g) for g in range(3)]
))
loop.close()

但它不起作用。任何人都知道如何使用该收集函数来处理以编程方式创建的函数列表？

明确一点：gather 函数不是我定义的，所以我不能从它的定义中删除 * 并简单地传递这样的参数列表。我需要 "unpack" 列表，但我不知道如何。

Answer 1

找到解决方案：

loop.run_until_complete(asyncio.gather(*(factorial(str(g),g) for g in range(3)))

Answer 2

您也可以使用 itertools.starmap 完成此任务：

import asyncio
import itertools

async def factorial(name, number):
    f = 1
    for i in range(2, number+1):
        print("Task %s: Compute factorial(%s)..." % (name, i))
        await asyncio.sleep(1)
        f *= i
    print("Task %s: factorial(%s) = %s" % (name, number, f))

loop = asyncio.get_event_loop()

args = [(str(g), g) for g in range(3)]
tasks = itertools.starmap(factorial, args)
loop.run_until_complete(asyncio.gather(*tasks))
loop.close()

Make an iterator that computes the function using arguments obtained from the iterable. Used instead of map() when argument parameters are already grouped in tuples from a single iterable (the data has been “pre-zipped”).

更多阅读：here

Answer 3

协程列表可以动态生成并传递如下：

import asyncio

async def factorial(name, number):
    f = 1
    for i in range(2, number + 1):
        print(f"Task {name}: Compute factorial({i})...")
        await asyncio.sleep(1)
        f *= i
    print(f"Task {name}: factorial({number}) = {f}")

async def main():
    a = factorial("A", 2)
    b = factorial("B", 3)
    c = factorial("C", 4)
    #
    # example passing in list of coroutines
    #
    await asyncio.gather(*[a,b,c])

asyncio.run(main())

Python - Asyncio - 将参数列表传递给用 * 定义的函数

Python - Asyncio - pass list of argument to function defined with *

python-asyncio