Book Image

Python Feature Engineering Cookbook - Second Edition

By : Soledad Galli
Book Image

Python Feature Engineering Cookbook - Second Edition

By: Soledad Galli

Overview of this book

Feature engineering, the process of transforming variables and creating features, albeit time-consuming, ensures that your machine learning models perform seamlessly. This second edition of Python Feature Engineering Cookbook will take the struggle out of feature engineering by showing you how to use open source Python libraries to accelerate the process via a plethora of practical, hands-on recipes. This updated edition begins by addressing fundamental data challenges such as missing data and categorical values, before moving on to strategies for dealing with skewed distributions and outliers. The concluding chapters show you how to develop new features from various types of data, including text, time series, and relational databases. With the help of numerous open source Python libraries, you'll learn how to implement each feature engineering method in a performant, reproducible, and elegant manner. By the end of this Python book, you will have the tools and expertise needed to confidently build end-to-end and reproducible feature engineering pipelines that can be deployed into production.
Table of Contents (14 chapters)

Setting up an entity set and creating features automatically

Relational datasets or databases contain data spread across multiple tables and the relationships between tables are dictated by a unique identifier that tells us how we can join those tables. To automate feature creation with Featuretools, first, we need to enter the different data tables and establish their relationships within what is called an entity set. The entity set then informs Featuretools how these tables are connected so that the library can automatically create features based on those relationships.

We will work with a dataset containing information about customers, invoices, and products. First, we will set up an entity set highlighting the relationships between these three items. This entity set will be the starting point for the remaining recipes in this chapter. Next, we will create features automatically by aggregating the data at the customer, invoice, and product levels, utilizing the default parameters...