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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 Jan 2020
Publisher Packt
ISBN-13 9781789806311
Length 372 pages
Edition 1st Edition
Languages
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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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Table of Contents (13) Chapters Close

Preface 1. Foreseeing Variable Problems When Building ML Models 2. Imputing Missing Data FREE CHAPTER 3. Encoding Categorical Variables 4. Transforming Numerical Variables 5. Performing Variable Discretization 6. Working with Outliers 7. Deriving Features from Dates and Time Variables 8. Performing Feature Scaling 9. Applying Mathematical Computations to Features 10. Creating Features with Transactional and Time Series Data 11. Extracting Features from Text Variables 12. Other Books You May Enjoy

Capturing missing values in a bespoke category

Missing data in categorical variables can be treated as a different category, so it is common to replace missing values with the Missing string. In this recipe, we will learn how to do so using pandas, scikit-learn, and Feature-engine.

How to do it...

To proceed with the recipe, let's import the required tools and prepare the dataset:

  1. Import pandas and the required functions and classes from scikit-learn and Feature-engine:
import pandas as pd
from sklearn.model_selection import train_test_split
from sklearn.impute import SimpleImputer
from feature_engine.missing_data_imputers import CategoricalVariableImputer
  1. Let's load the dataset:
data = pd.read_csv('creditApprovalUCI...
You have been reading a chapter from
Python Feature Engineering Cookbook
Published in: Jan 2020
Publisher: Packt
ISBN-13: 9781789806311
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