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Python Feature Engineering Cookbook

You're reading from   Python Feature Engineering Cookbook A complete guide to crafting powerful features for your machine learning models

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Product type Paperback
Published in Aug 2024
Publisher Packt
ISBN-13 9781835883587
Length 396 pages
Edition 3rd Edition
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Author (1):
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Soledad Galli Soledad Galli
Author Profile Icon Soledad Galli
Soledad Galli
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Toc

Table of Contents (14) Chapters Close

Preface 1. Chapter 1: Imputing Missing Data FREE CHAPTER 2. Chapter 2: Encoding Categorical Variables 3. Chapter 3: Transforming Numerical Variables 4. Chapter 4: Performing Variable Discretization 5. Chapter 5: Working with Outliers 6. Chapter 6: Extracting Features from Date and Time Variables 7. Chapter 7: Performing Feature Scaling 8. Chapter 8: Creating New Features 9. Chapter 9: Extracting Features from Relational Data with Featuretools 10. Chapter 10: Creating Features from a Time Series with tsfresh 11. Chapter 11: Extracting Features from Text Variables 12. Index 13. Other Books You May Enjoy

Performing ordinal encoding based on the target value

In the previous recipe, we replaced categories with integers, which were assigned arbitrarily. We can also assign integers to the categories given the target values. To do this, first, we calculate the mean value of the target per category. Next, we order the categories from the one with the lowest to the one with the highest target mean value. Finally, we assign digits to the ordered categories, starting with 0 to the first category up to k-1 to the last category, where k is the number of distinct categories.

This encoding method creates a monotonic relationship between the categorical variable and the response and therefore makes the variables more adequate for use in linear models.

In this recipe, we will encode categories while following the target value using pandas and feature-engine.

How to do it...

First, let’s import the necessary Python libraries and get the dataset ready:

  1. Import the required...
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