That Panda module is no joke. I can see that difficulty level is just gonna ramp up from here.

Man I tried using Pandas and NumPy on the side and it kicked my ass every step of the way. I think the most I did was generate a table and then give up.

That NATO alphabet code looks a lot simpler than I expected it would be - a couple days ago I had a though of that being a nice easy challenge for someone new to programming.

Python makes it easy to loop over lists, but sometimes you need a traditional C-style for loop that let's you use the iteration of the loop. I did some file operations in a script where I needed to use the index to know where to markup a file. This link is a helpful tutorial: https://treyhunner.com/2016/04/how-to-loop-with-indexes-in-python/

Pay attention to isPrime, that's a method implementation that comes up in job interviews from time to time. Prime numbers are only divisible by 1 and themselves, which allows you to shortcut some math by checking from 2 to n / 2. It's an optimization that pays off for large n. I think there's also some other mathematical trickery you can employ on that, but at that point you really aren't solving a computer science problem, but a math problem - as an interviewer I'd never expect or even want the mathematical answer.