如何使事件循環同時運行任務？

Question

我想在 asyncio 中同時調用兩個asyncio ，我用loop.create_task ，但我發現它實際上不是並發的。

這是我的代碼：

import asyncio


async def foo(v):
    print(f"start {v}")
    for i in range(5):
        print(f"work in {v}")
    print(f"done {v}")


def schedule_foo():
    print("out start 1")
    loop.create_task(foo(1))
    print("out start 2")
    loop.create_task(foo(2))


loop = asyncio.get_event_loop()
schedule_foo()
loop.run_forever()

這將是 output：

out start 1
out start 2
start 1
work in 1
work in 1
work in 1
work in 1
work in 1
done 1
start 2
work in 2
work in 2
work in 2
work in 2
work in 2
done 2

如您所見，主循環是異步的，但子任務實際上是同步的。

我的問題是how can I make the function run in concurrently actually ？

Answer 1

你忘了使用await ：

import asyncio

async def foo(v):
    print(f"start {v}")
    for i in range(5):
        print(f"work in {v}")
        await asyncio.sleep(0.1)
    print(f"done {v}")


def schedule_foo():
    print("out start 1")
    loop.create_task(foo(1))
    print("out start 2")
    loop.create_task(foo(2))


loop = asyncio.get_event_loop()
schedule_foo()
loop.run_forever()