Book Image

Machine Learning with R Cookbook, Second Edition - Second Edition

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

Machine Learning with R Cookbook, Second Edition - Second Edition

By: Yu-Wei, Chiu (David Chiu)

Overview of this book

Big data has become a popular buzzword across many industries. An increasing number of people have been exposed to the term and are looking at how to leverage big data in their own businesses, to improve sales and profitability. However, collecting, aggregating, and visualizing data is just one part of the equation. Being able to extract useful information from data is another task, and a much more challenging one. Machine Learning with R Cookbook, Second Edition uses a practical approach to teach you how to perform machine learning with R. Each chapter is divided into several simple recipes. Through the step-by-step instructions provided in each recipe, you will be able to construct a predictive model by using a variety of machine learning packages. In this book, you will first learn to set up the R environment and use simple R commands to explore data. The next topic covers how to perform statistical analysis with machine learning analysis and assess created models, covered in detail later on in the book. You'll also learn how to integrate R and Hadoop to create a big data analysis platform. The detailed illustrations provide all the information required to start applying machine learning to individual projects. With Machine Learning with R Cookbook, machine learning has never been easier.
Table of Contents (21 chapters)
Title Page
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Predicting labels based on a model trained by nnet


As we have trained a neural network with nnet in the previous recipe, we can now predict the labels of the testing dataset based on the trained neural network. Furthermore, we can assess the model with a confusion matrix adapted from the caret package.

Getting ready

To complete this recipe, you need to have completed the previous recipe by generating the training dataset, trainset, and the testing dataset, testset, from the iris dataset. The trained neural network also needs to be saved as iris.nn.

How to do it...

Perform the following steps to predict labels based on the trained neural network:

  1. Generate the predictions of the testing dataset based on the model, iris.nn:
        > iris.predict = predict(iris.nn, testset, type="class")
  1. Generate a classification table based on the predicted labels and labels of the testing dataset:
> nn.table = table(testset$Species, iris.predict)
iris.predict
       setosa versicolor virginica
setosa 17 0 0...