Book Image

Advanced Machine Learning with R

By : Cory Lesmeister, Dr. Sunil Kumar Chinnamgari
Book Image

Advanced Machine Learning with R

By: Cory Lesmeister, Dr. Sunil Kumar Chinnamgari

Overview of this book

R is one of the most popular languages when it comes to exploring the mathematical side of machine learning and easily performing computational statistics. This Learning Path shows you how to leverage the R ecosystem to build efficient machine learning applications that carry out intelligent tasks within your organization. You’ll work through realistic projects such as building powerful machine learning models with ensembles to predict employee attrition. Next, you’ll explore different clustering techniques to segment customers using wholesale data and even apply TensorFlow and Keras-R for performing advanced computations. Each chapter will help you implement advanced machine learning algorithms using real-world examples. You’ll also be introduced to reinforcement learning along with its use cases and models. Finally, this Learning Path will provide you with a glimpse into how some of these black box models can be diagnosed and understood. By the end of this Learning Path, you’ll be equipped with the skills you need to deploy machine learning techniques in your own projects.
Table of Contents (30 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

Building a text sentiment classifier with the BoW approach


The intent of the BoW approach is to convert the review text provided into a matrix form. It represents documents as a set of distinct words by ignoring the order and meaning of the words. Each row of the matrix represents each review (otherwise called a document in NLP), and the columns represent the universal set of words present in all the reviews. For each document, and across each word, the existence of the word, or the frequency of the word occurrence, in that specific document is recorded. Finally, the matrix created from word frequency vectors represents the documents set. This methodology is used to create input datasets that are required to train the models, and also to prepare the test dataset that need to be used by the trained models to perform text classification. Now that we understand the BoW motivation, let's jump into implementing the steps to build a sentiment analysis classifier based on this approach, as shown...