In Python, the mere act of making a function call incurs a relatively large amount of overhead. If some function is called repeatedly in a tight loop, even if it isn’t a long-running function ...

This can cause the loop to skip over elements. For example, when 1 is removed, 2 moves into 1's old position, but the loop's internal counter has already moved on, potentially skipping 2.

But for more features and flexibility, it's better to go with a good code editor or an IDE. For this tutorial, I'll be using Visual Studio Code. You can get it on any of the three operating systems.