For those who aren't familiar, katas are those impressive sequences of movements that you've surely seen martial arts guys perform. Code katas are the same idea applied to writing code: you solve a problem many times, mastering the movements, and then perform it for others.
My friend Corey Haines has worked with some other people to run a Katacast site dedicated to code katas, posting them roughly once per week. Recently, there's been a string of solutions to the same problem, with my Python version as this week's entry.
Briefly, here's the problem I solve. I have numbers coming in as a string, separated by commas or newlines. My job is to add those numbers and return the sum. There are two complications:
My screencasts always prompt questions about my Vim configuration, so take a look at my dotfiles repo if you're interested. For this kata, I'm slowing down intentionally – typing slower and inserting small, regular pauses so the viewer has time to look around a bit. I may post a "hard mode" version at full speed if people show interest.
Comments are encouraged, of course – the purpose of a kata is improvement!
If you like this, by the way, you may also enjoy the refactoring screencast I posted recently.