Book Image

Machine Learning with R Cookbook

By : Yu-Wei, Chiu (David Chiu)
Book Image

Machine Learning with R Cookbook

By: Yu-Wei, Chiu (David Chiu)

Overview of this book

<p>The R language is a powerful open source functional programming language. At its core, R is a statistical programming language that provides impressive tools to analyze data and create high-level graphics.</p> <p>This book covers the basics of R by setting up a user-friendly programming environment and performing data ETL in R. Data exploration examples are provided that demonstrate how powerful data visualization and machine learning is in discovering hidden relationships. You will then dive into important machine learning topics, including data classification, regression, clustering, association rule mining, and dimension reduction.</p>
Table of Contents (21 chapters)
Machine Learning with R Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Resources for R and Machine Learning
Dataset – Survival of Passengers on the Titanic
Index

Performing cross-validation with the boosting method


Similar to the bagging function, adabag provides a cross-validation function for the boosting method, named boosting.cv. In this recipe, we will demonstrate how to perform cross-validation using boosting.cv from the package, adabag.

Getting ready

In this recipe, we continue to use the telecom churn dataset as the input data source to perform a k-fold cross-validation with the boosting method.

How to do it...

Perform the following steps to retrieve the minimum estimation errors via cross-validation with the boosting method:

  1. First, you can use boosting.cv to cross-validate the training dataset:

    > churn.boostcv = boosting.cv(churn ~ ., v=10, data=trainset, mfinal=5,control=rpart.control(cp=0.01))
    
  2. You can then obtain the confusion matrix from the boosting results:

    > churn.boostcv$confusion
                   Observed Class
    Predicted Class  yes   no
                no   119 1940
                yes  223   33
    
  3. Finally, you can retrieve the average errors...