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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
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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

Aggregating transactions in a time window

When we want to predict an event at a certain point in time, often, transactions or values closer to the event tend to be more relevant. Then, if we want to predict whether a customer will churn next week, the information in the last weeks or months tends to be more informative than the transactions of the customer in the past 5 years.

We can use mathematical operations to summarize historical data, just like we did in the previous recipe, but only for a certain temporal window. This way, we can create features such as the maximum amount spent in the last week or the number of transactions in the last month, to name a few examples. In this recipe, we will summarize time series data over discrete time windows using pandas.

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