Deep Dive: Categorical Features

Understanding categorical features

Machine learning algorithms only work with numbers. If your data contains text features, for example, these would require transformation to numbers in some way. We learned in the previous lesson that the data for our case study is, in fact, entirely numerical. However, it’s worth thinking about how it got to be that way. In particular, consider the EDUCATION feature.

This is an example of what is called a categorical feature: you can imagine that as raw data, this column consisted of the text labels “graduate school,” “university,” “high school,” and “others.” These are called the levels of the categorical feature; here, there are four levels. It is only through a ...