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

Visualizing a recursive partitioning tree


From the last recipe, we learned how to print the classification tree in a text format. To make the tree more readable, we can use the plot function to obtain the graphical display of a built classification tree.

Getting ready

One needs to have the previous recipe completed by generating a classification model, and assign the model into the churn.rp variable.

How to do it...

Perform the following steps to visualize the classification tree:

  1. Use the plot function and the text function to plot the classification tree:

    > plot(churn.rp, margin= 0.1)
    > text(churn.rp, all=TRUE, use.n = TRUE)
    

    Figure 3: The graphical display of a classification tree

  2. You can also specify the uniform, branch, and margin parameter to adjust the layout:

    > plot(churn.rp, uniform=TRUE, branch=0.6, margin=0.1)
    > text(churn.rp, all=TRUE, use.n = TRUE)
    

    Figure 4: Adjust the layout of the classification tree

How it works...

Here, we demonstrate how to use the plot function to graphically...