When I create sample code for my students, I often include lots of comments for them, and it would be amazing if there was a simple way to toggle those comments on and off. Once students have processed the comments, hiding them and seeing a streamlined and uncluttered version of the code would be helpful.
If that feature existed, I also suspect that students might be more inclined to add comments to their own code more often.
Hi,
Welcome to the forum! 
Which code editor are your students using? Do they use the p5 web editor?
Because depending on the IDE, there might be functionalities to hide comments :
This is still open on VSCode : https://github.com/microsoft/vscode/issues/46505
For Sublime : How to hide comments - Technical Support - Sublime Forum
On JetBrains products (collapse doc strings): Is there any way to collapse just comments? – IDEs Support (IntelliJ Platform) | JetBrains
Atom : fold-comments
Brackets: GitHub - thehogfather/brackets-code-folding: Code folding extension for brackets IDE
And in the p5 web editor, you can fold functions, blocks and multiline comments but not single line comments. Feel free to open an issue on GitHub for a feature enhancement :