我有一些异步代码,它们在Python解释器(CPython 3.6.2)中运行良好。现在,我想在一个带有IPython内核的Jupyter笔记本中运行它。
我可以用以下命令运行它
import asyncio
asyncio.get_event_loop().run_forever()
虽然这似乎有效,但它似乎也阻碍了笔记本电脑,似乎与笔记本电脑玩得不好。
我的理解是Jupyter在引擎盖下使用了龙卷风,所以我尝试了install a Tornado event loop as recommended in the Tornado docs:
from tornado.platform.asyncio import AsyncIOMainLoop
AsyncIOMainLoop().install()
但是,这会产生以下错误:
---------------------------------------------------------------------------
AssertionError Traceback (most recent call last)
<ipython-input-1-1139449343fc> in <module>()
1 from tornado.platform.asyncio import AsyncIOMainLoop
----> 2 AsyncIOMainLoop().install()
~\AppData\Local\Continuum\Anaconda3\envs\numismatic\lib\site- packages\tornado\ioloop.py in install(self)
179 `IOLoop` (e.g., :class:`tornado.httpclient.AsyncHTTPClient`).
180 """
--> 181 assert not IOLoop.initialized()
182 IOLoop._instance = self
183
AssertionError:
最后我找到了下面的页面:http://ipywidgets.readthedocs.io/en/stable/examples/Widget%20Asynchronous.html
所以我用下面的代码添加了一个单元格:
import asyncio
from ipykernel.eventloops import register_integration
@register_integration('asyncio')
def loop_asyncio(kernel):
'''Start a kernel with asyncio event loop support.'''
loop = asyncio.get_event_loop()
def kernel_handler():
loop.call_soon(kernel.do_one_iteration)
loop.call_later(kernel._poll_interval, kernel_handler)
loop.call_soon(kernel_handler)
try:
if not loop.is_running():
loop.run_forever()
finally:
loop.run_until_complete(loop.shutdown_asyncgens())
loop.close()
在下一个单元格中,我运行:
%gui asyncio
这行得通,但我真的不明白为什么和如何行得通。有人能给我解释一下吗?
发布于 2018-12-02 23:30:56
在最新的jupyter版本中,这不再是一个问题!
https://blog.jupyter.org/ipython-7-0-async-repl-a35ce050f7f7
只需编写一个异步函数,然后直接在jupyter单元中等待它。
async def fn():
print('hello')
await asyncio.sleep(1)
print('world')
await fn()
发布于 2019-05-21 22:41:17
我和Asyncio在Jupyter中的顿悟时刻是这样的:
import time,asyncio
async def count():
print("count one")
await asyncio.sleep(1)
print("count four")
async def count_further():
print("count two")
await asyncio.sleep(1)
print("count five")
async def count_even_further():
print("count three")
await asyncio.sleep(1)
print("count six")
async def main():
await asyncio.gather(count(), count_further(), count_even_further())
s = time.perf_counter()
await main()
elapsed = time.perf_counter() - s
print(f"Script executed in {elapsed:0.2f} seconds.")
输出:
count one
count two
count three
count four
count five
count six
Script executed in 1.00 seconds.
最初是从这里开始的,但示例一开始对我来说并不清楚:https://realpython.com/async-io-python/
发布于 2018-07-20 19:03:13
我最近遇到了无法在Jupyter笔记本中运行异步代码的问题。这里讨论了这个问题:https://github.com/jupyter/notebook/issues/3397
我在讨论中尝试了其中一个解决方案,到目前为止它解决了问题。
pip3 install tornado==4.5.3
这取代了默认安装的tornado版本5.x。
然后,Jupyter笔记本中的异步代码按预期运行。
https://stackoverflow.com/questions/47518874
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