Recently I found an error like this: Javascript Error: IPython is not defined.
I’m currently working with the newest version of Anaconda, and I’m facing a problem while trying to generate plots in Python on JupyterLab. The specific error that appears is:
“Javascript Error: IPython is not defined.”
What’s curious is that when I execute the identical script in Spyder using an IPython kernel, it operates smoothly without any issues. Despite thorough online research, I’ve been unable to identify the root of this problem. I would be very thankful for any help or suggestions.
How to resolve this issue
Jupyter Lab supports interactive plotting with matplotlib using the jupyter-matplotlib extension. Although installing it is a bit more complex, it works well. Keep in mind that the ipympl version for Jupyter Lab requires NodeJS, which in turn needs Windows 8.1 or higher. So, if you’re using ipympl, your system should meet this requirement.
Before you start plotting, remember to activate the IPython magic command:
To use it, enter this in your notebook:
%matplotlib widget
For installation, here are the steps. If you’re working with Jupyter Lab, it’s better to use a version that’s 3 or higher. For more comprehensive instructions, especially for older versions, you can check out the ipympl GitHub page.
Using Conda: Install ipympl via conda-forge:
conda install -c conda-forge ipympl
If you’re using JupyterLab version 2:
- First, install NodeJS:
conda install nodejs - Then, install the necessary Jupyter Lab extensions and build:
jupyter labextension install @jupyter-widgets/jupyterlab-manager
jupyter lab build - For updating an existing installation of Jupyter Lab:
Simply install ipympl and rebuild Jupyter Lab:
conda install ipympl
jupyter lab build
Using Pip: For pip users, the process is similar:
Install ipympl:
pip install ipympl
For JupyterLab 2 users:
- Install NodeJS:
pip install nodejs-bin - Install the necessary extensions for Jupyter Lab:
jupyter labextension install @jupyter-widgets/jupyterlab-managerjupyter labextension install jupyter-matplotlib
Some other tips on this:
- Update JupyterLab and IPython to their latest versions.
- Ensure all necessary JupyterLab extensions are installed and enabled.
- Try running JupyterLab in a different browser or in incognito mode to check if browser extensions are causing the issue.
- If you suspect a corrupted installation, reinstall JupyterLab.
- Review any custom JavaScript in your notebooks for potential conflicts.