This is most likely an issue with your backend setting. If you want your plots to show up inline (inside of your notebook) import with this added line:
import matplotlib.pyplot as plt
%matplotlib inline
To have your plots show up interactively inline (inside your notebook) import with this line instead:
import matplotlib.pyplot as plt
%matplotlib notebook
To have your plots show up outside of your notebook (in a new window), import with this line instead:
import matplotlib.pyplot as plt
%matplotlib qt
NOTE: You need to restart the kernel to switch between inline notebook and outside qt to avoid the error: Warning: Cannot change to a different GUI toolkit
Finally, if issues persist, the following might help uncover what is going on:
import matplotlib
matplotlib.get_backend()
If using any of the options above, it should output one of the following:
- 'module://ipykernel.pylab.backend_inline'
- 'nbAgg'
- 'Qt4Agg'