Jupyter Notebook with Python 3.8 - NotImplementedError

Question

Upgraded recently to Python 3.8, and installed jupyter. However, when trying to run jupyter notebook getting the following error:

  File "c:\users\user\appdata\local\programs\python\python38\lib\site-packages\tornado\platform\asyncio.py", line 99, in add_handler
    self.asyncio_loop.add_reader(fd, self._handle_events, fd, IOLoop.READ)
  File "c:\users\user\appdata\local\programs\python\python38\lib\asyncio\events.py", line 501, in add_reader
    raise NotImplementedError
NotImplementedError

I know Python 3.8 on windows switched to ProactorEventLoop by default, so I suspect it is related to this.

Jupyter does not support Python 3.8 at the moment? Is there a work around?

Python 3.8 is very fresh so better go back to 3.7 and wait some time till it will be better tested and modules will be create specially for 3.8. — furas
– furas, Commented Oct 17, 2019 at 1:06
Possible duplicate of Jupyter notebook cannot start with python 3.8 in Windows 10 — FObersteiner
– FObersteiner, Commented Nov 5, 2019 at 17:07
This is now fixed in version 6.0.3 of jupyter notebook. Upgrade with pip install notebook --upgrade — drec4s
– drec4s, Commented Jan 22, 2020 at 12:33

Udi · Accepted Answer · 2020-02-28 06:35:51Z

201

+100

EDIT

This issue exists in older versions of Jupyter Notebook and was fixed in version 6.0.3 (released 2020-01-21). To upgrade to the latest version run:

pip install notebook --upgrade

~~Following on this issue through GitHub, it seems the problem is related to the tornado server that jupyter uses.~~

For those that can't wait for an official fix, I was able to get it working by editing the file tornado/platform/asyncio.py, by adding:

import sys if sys.platform == 'win32': asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())

After the main imports.

I expect an official fix for this soon, however.

edited Feb 28, 2020 at 6:35

Udi

30.8k9 gold badges105 silver badges134 bronze badges

answered Oct 17, 2019 at 10:06

drec4s

8,1178 gold badges35 silver badges56 bronze badges

Sign up to request clarification or add additional context in comments.

13 Comments

Andrew Over a year ago

Do not expect a fix from Tornado team: github.com/tornadoweb/tornado/issues/2608

Bheid Over a year ago

if you were looking for asyncio.py, take a look at "C:\Python3\Lib\site-packages\tornado\platform"

Omri374 Over a year ago

Thanks! If you're using a conda env, Make sure to change the version in the env and not only the global one. Second, make sure you add this change after the import asyncio statement :)

Isaiah Hines Over a year ago

This fixed it for me. In particular: 1. You can get the file location from the stack trace if you run: jupyter -m notebook 2. On my system the file is located here: C:\Users_NAME_\AppData\Roaming\Python\Python38\site-packages\tornado\platform\asyncio.py

Worm Over a year ago

This didn't work for me January 2020, Python3.8 but Mirwise Khan's answer below did

|

Mirwise Khan · Accepted Answer · 2024-05-21 07:48:59Z

45

Revising the answer in 2020

Change the end part of the file C:\Users\{USER-NAME}\AppData\Local\Programs\Python\Python38\Lib\asyncio\__init__.py

From

if sys.platform == 'win32':  # pragma: no cover
    from .windows_events import *
    __all__ += windows_events.__all__
else:
    from .unix_events import *  # pragma: no cover
    __all__ += unix_events.__all__

To

import asyncio

if sys.platform == 'win32':
    from .windows_events import *
    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
    __all__ += windows_events.__all__
else:
    from .unix_events import *  # pragma: no cover
    __all__ += unix_events.__all__

edited May 21, 2024 at 7:48

answered Dec 28, 2019 at 15:23

Mirwise Khan

1,42819 silver badges29 bronze badges

7 Comments

Sundeep Over a year ago

Both the question and accepted answer were from October 2019 and the solution worked for me

Abhishek Agarwal Over a year ago

The accepted answer didn't work for me. this did. Thanks!

fuomag9 Over a year ago

Worked for me too, python 3.8 in jan 2020

Martijn Pieters Over a year ago

I would not go and alter Python's standard library source code.

Martijn Pieters Over a year ago

You can do this anywhere else, like in site.py.

|

penguins · Accepted Answer · 2020-11-02 19:14:58Z

3

For me, I had to reinstall asyncio

pip install asyncio --upgrade

And upgrade the kernel package

pip install ipykernel --upgrade

answered Nov 2, 2020 at 19:14

penguins

861 silver badge8 bronze badges

Comments

ming · Accepted Answer · 2021-07-28 06:27:08Z

0

I solved this problem by changing the python version from 3.9 to 3.7. (Windows).

answered Jul 28, 2021 at 6:27

ming

4451 gold badge5 silver badges14 bronze badges

Collectives™ on Stack Overflow

Jupyter Notebook with Python 3.8 - NotImplementedError

4 Answers 4

13 Comments

7 Comments

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

13 Comments

7 Comments

Comments

Comments

Linked

Related