Matplotlib shows 'agg backend' warning and won't display plots in PyCharm IDE

Backend
1

I’m having trouble displaying a basic chart using matplotlib in PyCharm. When I run this code:

import matplotlib.pyplot as plt
plt.plot([2,4,6],[8,3,9])
plt.show()

The plot window doesn’t open and I see this warning message:

UserWarning: Matplotlib is currently using agg, which is a non-GUI backend, so cannot show the figure.

I tried to fix this by changing the backend like this:

import matplotlib
matplotlib.use('TkAgg')
import matplotlib.pyplot as plt

But then I get this error:

ModuleNotFoundError: No module named 'tkinter'

When I try to install tkinter using pip, it fails:

Collecting tkinter
  Could not find a version that satisfies the requirement tkinter (from versions: )
No matching distribution found for tkinter

What’s the best way to solve this issue and get matplotlib to show my plots properly?

2

tkinter is already part of Python’s standard library and does not need to be installed separately. If you’re facing a ModuleNotFoundError, it suggests that your Python installation might be incomplete or you may be using a version that lacks tkinter. I’ve encountered similar issues with minimal Python distributions. Consider using the Qt5Agg backend instead of TkAgg; you can set this up by adding matplotlib.use('Qt5Agg') after installing PyQt5 via pip install PyQt5. Additionally, you can enable PyCharm’s scientific mode by navigating to Settings > Tools > Python Scientific and checking the corresponding box, which will automatically handle backend configurations and display plots directly within the IDE.

3

check your pyCharm settings first - go to run configurations and enable “run with python console.” this usually fixes backend issues without touching matplotlib settings. also try running the same code in terminal to see if it’s pyCharm-specific.

4

Hmm, interesting - what OS are you on? Sometimes this stuff’s OS-specific. Try plt.savefig('test.png') instead of plt.show() to see if matplotlib works at all. That’ll tell us if it’s just a display problem or something worse.