Javascript Error: IPython is not defined in JupyterLab

Jupyter Lab does support interactive matplotlib through the jupyter-matplotlib extension. The installation procedure is slightly more involved, but works fine. Since the ipympl Jupyter Lab version requires NodeJS, and NodeJS requires Windows 8.1, ipympl also has this requirement.

As before, it is important to invoke the iPython magic command before plotting:

Usage:

%matplotlib widget

Installation:

Note: If using this extension with Jupyter Lab, it's recommended to use a version >= 3. For more detailed instructions on installing an old extension than below, see the instructions on ipympl github.

Using conda

conda install -c conda-forge ipympl

# If using JupyterLab 2
conda install nodejs
jupyter labextension install @jupyter-widgets/jupyterlab-manager
jupyter lab build

# Later, if updating a previous Lab install:
conda install ipympl
jupyter lab build

Using pip

pip install ipympl

# If using JupyterLab 2
pip install nodejs
jupyter labextension install @jupyter-widgets/jupyterlab-manager
jupyter labextension install jupyter-matplotlib

Jupyter Lab does support interactive matplotlib through the jupyter-matplotlib extension. See TomNorway's answer.

Alternatively, you can configure matplotlib to use inline instead. inline is not as powerful as interactive, but it can save you.

To use inline, add this line before plot the graph:

    %matplotlib inline

More Info

1. Jupyterlab supports jpympl.

2. You must put %matplotlib widget in the very beginning of the jupyterlab.

You can change to %matplotlib inline in specific cell, and active %matplotlib widget again if needed.

Otherwise, no matter how many times you reinstall the package, you will still get the errors.

Encountered similar issue when using backtrader. This fixed it for me:

cerebro.plot(iplot = False)