我正在尝试致电
asyncio.create_task()
,但我正在处理一个错误:
这是一个例子:
import asyncio
import time
async def async_say(delay, msg):
await asyncio.sleep(delay)
print(msg)
async def main():
task1 = asyncio.create_task(async_say(4, 'hello'))
task2 = asyncio.create_task(async_say(6, 'world'))
print(f"started at {time.strftime('%X')}")
await task1
await task2
print(f"finished at {time.strftime('%X')}")
loop = asyncio.get_event_loop()
loop.run_until_complete(main())
出:
AttributeError: module 'asyncio' has no attribute 'create_task'
所以我尝试使用以下代码片段(
.ensure_future()
),没有任何问题:
async def main():
task1 = asyncio.ensure_future(async_say(4, 'hello'))
task2 = asyncio.ensure_future(async_say(6, 'world'))
print(f"started at {time.strftime('%X')}")
await task1
await task2
print(f"finished at {time.strftime('%X')}")
loop = asyncio.get_event_loop()
loop.run_until_complete(main())
出:
started at 13:19:44
hello
world
finished at 13:19:50
[注意]:
[更新]:
借用@user4815162342回答,我的问题解决了:
async def main():
loop = asyncio.get_event_loop()
task1 = loop.create_task(async_say(4, 'hello'))
task2 = loop.create_task(async_say(6, 'world'))
print(f"started at {time.strftime('%X')}")
await task1
await task2
print(f"finished at {time.strftime('%X')}")
loop = asyncio.get_event_loop()
loop.run_until_complete(main())
create_task
顶级函数是在Python 3.7中添加的,而您正在使用Python 3.6。在 3.7 之前,create_task
仅可用作事件循环中的 方法,因此您可以像这样调用它:
async def main():
loop = asyncio.get_event_loop()
task1 = loop.create_task(async_say(4, 'hello'))
task2 = loop.create_task(async_say(6, 'world'))
# ...
await task1
await task2
asyncio.ensure_future
也可以工作,但是当您知道自己正在处理协程时,create_task
更明确,并且是 首选 选项。
我确实喜欢这个
if __name__ == '__main__':
asyncio.get_event_loop().run_until_complete(scheduled(4))