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 multivariate data using biplot


In order to find out how data and variables are mapped in regard to the principal component, you can use biplot, which plots data and the projections of original features on to the first two components. In this recipe, we will demonstrate how to use biplot to plot both variables and data on the same figure.

Getting ready

Ensure that you have completed the previous recipe by generating a principal component object and save it in the variable, swiss.pca.

How to do it...

Perform the following steps to create a biplot:

  1. You can create a scatter plot using component 1 and 2:

    >  plot(swiss.pca$x[,1], swiss.pca$x[,2], xlim=c(-4,4))
    > text(swiss.pca$x[,1], swiss.pca$x[,2], rownames(swiss.pca$x), cex=0.7, pos=4, col="red")
    

    The scatter plot of first two components from PCA result

  2. If you would like to add features on the plot, you can create biplot using the generated principal component object:

    > biplot(swiss.pca)
    

    The biplot using PCA result

How it works...