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Hands-On Machine Learning with scikit-learn and Scientific Python Toolkits

You're reading from   Hands-On Machine Learning with scikit-learn and Scientific Python Toolkits A practical guide to implementing supervised and unsupervised machine learning algorithms in Python

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Product type Paperback
Published in Jul 2020
Publisher Packt
ISBN-13 9781838826048
Length 384 pages
Edition 1st Edition
Languages
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Author (1):
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Tarek Amr Tarek Amr
Author Profile Icon Tarek Amr
Tarek Amr
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Table of Contents (18) Chapters Close

Preface 1. Section 1: Supervised Learning
2. Introduction to Machine Learning FREE CHAPTER 3. Making Decisions with Trees 4. Making Decisions with Linear Equations 5. Preparing Your Data 6. Image Processing with Nearest Neighbors 7. Classifying Text Using Naive Bayes 8. Section 2: Advanced Supervised Learning
9. Neural Networks – Here Comes Deep Learning 10. Ensembles – When One Model Is Not Enough 11. The Y is as Important as the X 12. Imbalanced Learning – Not Even 1% Win the Lottery 13. Section 3: Unsupervised Learning and More
14. Clustering – Making Sense of Unlabeled Data 15. Anomaly Detection – Finding Outliers in Data 16. Recommender System – Getting to Know Their Taste 17. Other Books You May Enjoy

Using singular value decomposition

The user-item rating matrix is usually a huge matrix. The one we got from our dataset here comprises 30,114 rows and 19,228 columns, and most of the values in this matrix (99.999%) are zeros. This is expected. Say you own a streaming service with thousands of movies in your library. It is very unlikely that a user will watch more than a few dozen of them. This sparsity creates another problem. If one user watched the movie The Hangover: Part 1 and another user watched The Hangover: Part 2, from the matrix's point of view, they watched two different movies. We already know that collaborative filtering algorithms don't use users or item features. Thus, it is not aware of the fact that the two parts of The Hangover movie belong to the same franchise, let alone knowing that they both are comedies. To deal with this shortcoming, we need to transform our user-item rating matrix. We want the new matrix, or matrices, to be smaller and to capture...

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