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Python Feature Engineering Cookbook

You're reading from   Python Feature Engineering Cookbook Over 70 recipes for creating, engineering, and transforming features to build machine learning models

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Product type Paperback
Published in Oct 2022
Publisher Packt
ISBN-13 9781804611302
Length 386 pages
Edition 2nd Edition
Languages
Tools
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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 2. Chapter 2: Encoding Categorical Variables FREE CHAPTER 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 mean or median imputation

Mean or median imputation consists of replacing missing values with the mean or median variable. The mean or median is calculated using a train set, and these values are used to impute missing data in train and test sets, as well as in all future data we intend to use with the machine learning model. Scikit-learn and feature-engine transformers learn the mean or median from the train set and store these parameters for future use out of the box. In this recipe, we will perform mean and median imputation using pandas, scikit-learn, and feature-engine.

Tip

Use mean imputation if variables are normally distributed and median imputation otherwise. Mean and median imputation may distort the distribution of the original variables if there is a high percentage of missing data.

How to do it...

Let’s begin this recipe:

  1. First, we’ll import pandas and the required functions and classes from scikit-learn and feature-engine:
    import...
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