Matplotlib image not coming up in Visual Studio Code on Mac

Question

I'm running some basic code in the Visual Studio Code editor on MacOSX:

    import matplotlib.pyplot as plt
    import numpy as np
    x = np.linspace(0, 20, 100)
    plt.plot(x, np.sin(x))
    plt.show()

...and can't seem to get the png/svg file image to come up after running this. This also doesn't stop executing and I have to manually terminate the process. However, if I run this directly in the Terminal (each line of code line for line) I get the resulting image. One work-around is to just save the file (plt.savefig('foo.png')). This seems to work - the image is saved in the specified file location. However, it would be good to just see the image come up after running the code.

Answer 1

When running matplotlib codes from the terminal, I experience the same kind of hanging of the application after saving the image to a file. In this case, one 'workaround' that has always worked for me is to turn off blocking. Basically alter your code in this way:

import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0, 20, 100)
plt.plot(x, np.sin(x))
plt.show(block=False)
input('press <ENTER> to continue')

It's not perfect, but the image is saved correctly and the application stops after you hit ENTER in the terminal. Hope this helps.

Answer 2

I am having a similar issue and I think it is a problem with the exact version of python that vs code is using to run the code.

For reference, I have vscode version 1.52.1 on a mac os Catalina. I installed python via anaconda and created a new environment for python 2.7 (tried with python 3.8 too). I open VSCode by calling code . from the folder I have my simple python codes saved in.

Like OP, I could reproduce the figure if I were to run the code from a python instance called from terminal but not from vscode.

MY SOLUTION: From vscode, select as python interpreter the one found in /usr/bin/python not the one in ~/opt/anaconda3/env/python27/bin/python

But this is weird, because from a separate terminal window which python returns ~/opt/anaconda3/env/python27/bin/python. This suggests me (though I am no python expert) that there is an issue within vscode about linking the right interpreter with the libraries. Frankly being new to vscode, I find the need to pay attention to these details quite concerning.

Answer 3

I got the same problem, which was driving me nuts. The image was displayed when using Jupyter Notebooks, but not always when using VS Code. I just added one last line_ plt.show() - IMHO unnecessarily - but this worked well.

import matplotlib.pyplot as plt
import matplotlib.image as img

im = img.imread('myimage.png')
plt.imshow(im)
plt.show() # <- added this line and now the image shows every time!