x lines of Python: machine learning

Is this really the world we live in? After reminding you about the SEG machine learning contest just before Christmas, I thought I could show you how you train a model in a supervised learning problem, then use it to make predictions on unseen data. So we'll just break a simple contest entry down into ten easy steps (note that you could do this on anything, doesn't have to be this problem). Before we start, let's review quickly what a machine learning problem looks like, and introduct a bit of jargon. To begin, we have a dataset (e.g.