Plots are not visible using matplotlib plt.show()

Question

I'm really new in Python and Linux and I need help, I tried to use matplotlib for showing a simple plot in the following way:

from matplotlib import pyplot as plt

plt.plot([5,6,7,8], [7,3,8,3])
plt.show()

But, when I run python3 test.py, I get the following output:

/usr/local/lib/python3.4/dist-packages/matplotlib/backends/backend_gtk3agg.py:18: UserWarning: The Gtk3Agg backend is known to not work on Python 3.x with pycairo. Try installing cairocffi.
  "The Gtk3Agg backend is known to not work on Python 3.x with pycairo. "
Traceback (most recent call last):
  File "/usr/local/lib/python3.4/dist-packages/matplotlib/backends/backend_gtk3agg.py", line 69, in on_draw_event
    buf, cairo.FORMAT_ARGB32, width, height)
NotImplementedError: Surface.create_for_data: Not Implemented yet.
Traceback (most recent call last):
  File "/usr/local/lib/python3.4/dist-packages/matplotlib/backends/backend_gtk3agg.py", line 69, in on_draw_event
    buf, cairo.FORMAT_ARGB32, width, height)
NotImplementedError: Surface.create_for_data: Not Implemented yet.
/usr/local/lib/python3.4/dist-packages/matplotlib/backends/backend_gtk3.py:215: Warning: Source ID 7 was not found when attempting to remove it
  GLib.source_remove(self._idle_event_id)

and an empty figure without white canvas:

What is wrong? How can I fix it?

Answer 1

As you can see:

"The Gtk3Agg backend is known to not work on Python 3.x with pycairo."

And so the suggestion presented is:

Try installing cairocffi.

The installation guide for cairocffi is pretty straight-forward. If the dependencies¹ are met it is as simple as:

pip install cairocffi

---

^{1) The dependencies for Python 3.x should logically be:}

sudo apt-get install python3-dev
sudo apt-get install libffi-dev