We have recently looked a lot more into ML.NET which will result in a range of new features on elmah.io. While the documentation from Microsoft is good, it is split up into multiple pieces which can make it hard to figure out how to build a real-world example with ML.NET. In this post, I will show you one of the pieces that I believe are missing: how to train and retrain a model.

My previous blog post about ML.NET, Find anomalies with spike detection and ML.NET, was based on a simple fire and forget part of ML.NET where you don’t need to train a model. In this post, the goal is to train a model to make movie recommendations. To simplify the example, I want to create a prediction if a person likes Die Hard or not, based on movie preferences.