Python Feature Engineering Cookbook

Combining pairs of features with mathematical functions

In the previous recipe, Combining multiple features with statistical operations, we created new features by performing statistical operations across several variables. Some mathematical operations, however, such as subtraction or division, make more sense when performed between two features, or when considering multiple features against one reference variable. These operations are very useful to derive ratios, such as the debt-to-income ratio:

debt-to-income ratio = total debt / total income

Or we can use them for differences, for example, the disposable income:

disposable income = income - total debt

In this recipe, we will learn how to derive new features by subtraction or division ...