Book Image

R Machine Learning Essentials

By : Michele Usuelli
Book Image

R Machine Learning Essentials

By: Michele Usuelli

Overview of this book

Table of Contents (15 chapters)
R Machine Learning Essentials
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Exploring and visualizing the features


After having defined the features, we can explore them and identify how they are related to the problem. In this section, you will see how to explore the data and define some simple charts.

Let's start with a feature, for instance, mainhue, which displays the predominant color of a flag. We want to identify the most common predominant colors, and for that purpose, we can use table to count the number of occurrences of each possible value. We can extract the mainhue column from dtFlag and apply table to it:

table(dtFlag[, mainhue])
black   blue  brown   gold  green orange    red  white 
     5     40      2     19     31      4     71     22

The three most common predominant colors are red, blue, and green. Please note that we could have put table inside the square brackets, obtaining the same result with cleaner code: dtFlag[, table(mainhue)].

How can we perform the same operation over any other column? First, let's define a string called nameCol that...