Mastering pandas - Second Edition

Constructing a model using Patsy for scikit-learn

Before we start our tour of the machine learning algorithms, we need to know a little bit about the Patsy library. We will make use of Patsy to design features that will be used in conjunction with scikit-learn. Patsy is a package for creating what is known as design matrices. These design matrices are transformations of the features in our input data. The transformations are specified by expressions known as formulas, which correspond to a specification of what features we wish the machine learning program to utilize in learning.

A simple example of this is as follows: suppose that we wish to linearly regress a variable, y, against some other variables—x, a, and b—and the interaction between ...