jupyterlab interactive plot

As per Georgy's suggestion, this was caused by Node.js not being installed.

To enable the jupyter-matplotlib backend, use the matplotlib Jupyter magic:

%matplotlib widget
import matplotlib.pyplot as plt
plt.figure()
x = [1,2,3]
y = [4,5,6]
plt.plot(x,y)

More info here jupyter-matplotlib on GitHub

JupyterLab 3.0+

1. Install jupyterlab and ipympl.

   For pip users:

   pip install --upgrade jupyterlab ipympl
   

   For conda users:

   conda update -c conda-forge jupyterlab ipympl
   

2. Restart JupyterLab.

3. Decorate the cell containing plotting code with the header:

   %matplotlib widget
   
   # plotting code goes here
   

JupyterLab 2.0

1. Install nodejs, e.g. conda install -c conda-forge nodejs.

2. Install ipympl, e.g. conda install -c conda-forge ipympl.

3. [Optional, but recommended.] Update JupyterLab, e.g.
   conda update -c conda-forge jupyterlab==2.2.9==py_0.

4. [Optional, but recommended.] For a local user installation, run:
   export JUPYTERLAB_DIR="$HOME/.local/share/jupyter/lab".

5. Install extensions:

    jupyter labextension install @jupyter-widgets/jupyterlab-manager
    jupyter labextension install jupyter-matplotlib
   

6. Enable widgets: jupyter nbextension enable --py widgetsnbextension.

7. Restart JupyterLab.

8. Decorate with %matplotlib widget.