Getting started with classification

Movie recommendation can be framed as a machine learning classification problem. If it is predicted that you’ll like a movie because you’ve liked or watched similar movies, for example, then it will be on your recommended list; otherwise, it won’t. Let’s get started by learning the important concepts of machine learning classification.

Classification is one of the main instances of supervised learning. Given a training set of data containing observations and their associated categorical outputs, the goal of classification is to learn a general rule that correctly maps the observations (also called features or predictive variables) to the target categories (also called labels or classes). Putting it another way, a trained classification model will be generated after the model learns from the features and targets of training samples, as shown in the first half of Figure 2.1. When new or unseen data comes in, the trained...