I have been using Jupyter for some time now and it has worked just fine. I have Jupyter and Python installed via Homebrew. I am running on MacOS.
Yesterday, I ran the command brew upgrade and now my Jupyter notebook is unable to find any of the installed python packages. I will use Numpy as the example.
When inside of a Jupyter notebook, I try to do
import numpy
I get the message:
ModuleNotFoundError: No module named 'numpy'
If, however, I launch python in a terminal window, then I can import Numpy without issue.
I first checked that the package was installed correctly by re-issuing the install command
brew install numpy
which outputs:
Warning: numpy 1.18.4 is already installed and up-to-date
To reinstall 1.18.4, run `brew reinstall numpy`
I also ran
pip install numpy
and got:
Requirement already satisfied: numpy in /usr/local/lib/python3.7/site-packages (1.18.4)
Now, this is where I got confused because I expected the path to point to something like /usr/local/Cellar/, so I checked the path inside of the Jupyter notebook:
import sys
sys.path
which outputs:
['/Users/kseuro/Dropbox/Dev/',
'/usr/local/Cellar/jupyterlab/2.1.2/libexec/lib/python38.zip',
'/usr/local/Cellar/jupyterlab/2.1.2/libexec/lib/python3.8',
'/usr/local/Cellar/jupyterlab/2.1.2/libexec/lib/python3.8/lib-dynload',
'/usr/local/opt/python@3.8/Frameworks/Python.framework/Versions/3.8/lib/python3.8',
'',
'/usr/local/Cellar/jupyterlab/2.1.2/libexec/lib/python3.8/site-packages',
'/usr/local/Cellar/jupyterlab/2.1.2/libexec/lib/python3.8/site-packages/IPython/extensions',
'/Users/kseuro/.ipython']
Ok, so Homebrew wants Jupyter to use Python3.8? So I tried brew switch python 3.8 and got:
Error: python does not have a version "3.8" in the Cellar.
python's installed versions: 3.7.7
I feel like I'm out of my depth now and need help figuring out what to do next. I don't want to start by just changing paths around.
Suggestions? Thanks so much.
I figured out what to do — posting the solution for my future self and others who may stumble upon this.
Since Jupyerlab is in its own Cellar, the Python packages need to end up in the
/usr/local/Cellar/jupyterlab/x.y.z/libexec/lib/python3.x/site-packages
directory, where x, y, z are integers, so that the Jupyter kernel can find them.
You can do this by calling:
import sys
!{sys.executable} -m pip install 'package-name'
inside of the Jupyer notebook.
All is well, again.