MatplotLib graphs

Can I use matplotlib to generate graphs from my data?¶

Yes you can, and your graphs will be saved as an image file in your directory.

The block of code below gives you an example of how you would do this:

import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt

fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(range(100))

fig.savefig("graph.png")

graph.png will then show up in your home directory. Simply put, wherever you might normally use plt.show() to display your graph on screen you should use fig.savefig('your_graph.png') to save it as an image file instead.

Once you've done that, you can view the graph from your browser using a URL like this: https://www.pythonanywhere.com/user/your-username/files/home/your-username/graph.png

What do do if you're seeing errors about Tkinter¶

Make sure to include the matplotlib.use("Agg") line from the example above -- that's the bit that sets the "backend" that matplotlib uses to draw graphics. Tkinter is the default, but it won't work on PythonAnywhere. Agg works fine...

(See this page on tkinter for more info).

Jupyter Notebooks¶

With all that said, probably your best bet for working interactively with data and graphs is to use a Jupyter Notebook. That's a premium feature on PythonAnywhere however...