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)

Extracting Features from Date and Time Variables

Date and time variables are those that contain information about dates, times, or both. In programming, we refer to these variables as datetime variables. Examples of datetime variables include date of birth, the time of an event, and date of last payment. The cardinality of datetime variables is usually very high. This means they contain a multitude of unique values, each corresponding to a specific combination of date and/or time. Therefore, we do not utilize datetime variables in their raw format in machine learning models. Instead, we enrich the dataset by extracting multiple features from these variables. In this chapter, we will learn how to extract new features from date and time by utilizing the pandas dt module. Later on, we will automate feature extraction over multiple variables with Feature-engine.

This chapter will cover the following recipes:

  • Extracting features from dates with pandas
  • Extracting features...