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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
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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

Extracting features from time with pandas

Some events occur more often at certain times of the day – for example, fraudulent activity is more likely to occur during the night or early morning. Air pollutant concentration also changes with the time of the day, with peaks at rush hour when there are more vehicles on the streets. Therefore, deriving time features is extremely useful. In this recipe, we will extract different time parts of a datetime variable by utilizing pandas and NumPy.

Getting ready

The following are some of the features that we can extract offtheshelf using pandas:

  • pandas.Series.dt.hour
  • pandas.Series.dt.minute
  • pandas.Series.dt.second

How to do it...

To proceed with this recipe, we must import the necessary libraries and create a toy dataset:

  1. Let’s import pandas and numpy:
    import numpy as np
    import pandas as pd
  2. Let’s create 20 datetime observations, beginning from 2019-03-05 at midnight followed by increments...
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