After I had the message “matplotlib” not found, I went to the button “packages” (shell tab?) searched for matplotlib, and could initiate the install process. Back in the console, it says “Installation failed”. Maybe it is only matplotlib, but I can not run most of my replits.
I suggest you try re-installing it using the Packages in Tools.
There has been a time where I accidentally uninstalled pip and another package, my Repl broke without the required packages, and I couldn’t reinstall anything. If this is the case, then all you can do is re-fork to another Repl.
Thank you for your advice. I could install something; obviously, the library is now recognized. But, unfortunately, the output (plot) is not appearing. Furthermore, doing the shell operation with all my other files could be more straightforward.