This is just a list of some great resources for learning programming.
Regular Expressions are a super effective way to deal with parsing text, which comes up all the time. Regex101 is an awesome tool for testing and seeing what your regex does Cons: Looks like garbley-gook for beginners. Some people write un-readable ones.
Being able to write a custom vim cmd is super handy and this is the place to learn. LearnVimScriptTheHardWay