Overview of this book

With huge amounts of data being generated every moment, businesses need applications that apply complex mathematical calculations to data repeatedly and at speed. With machine learning techniques and R, you can easily develop these kinds of applications in an efficient way. Practical Machine Learning with R begins by helping you grasp the basics of machine learning methods, while also highlighting how and why they work. You will understand how to get these algorithms to work in practice, rather than focusing on mathematical derivations. As you progress from one chapter to another, you will gain hands-on experience of building a machine learning solution in R. Next, using R packages such as rpart, random forest, and multiple imputation by chained equations (MICE), you will learn to implement algorithms including neural net classifier, decision trees, and linear and non-linear regression. As you progress through the book, you’ll delve into various machine learning techniques for both supervised and unsupervised learning approaches. In addition to this, you’ll gain insights into partitioning the datasets and mechanisms to evaluate the results from each model and be able to compare them. By the end of this book, you will have gained expertise in solving your business problems, starting by forming a good problem statement, selecting the most appropriate model to solve your problem, and then ensuring that you do not overtrain it.
Free Chapter
An Introduction to Machine Learning
Data Cleaning and Pre-processing
Feature Engineering
Introduction to neuralnet and Evaluation Methods
Linear and Logistic Regression Models
Unsupervised Learning

Adding Features to a Data Frame

We will look at the code to add new columns to an R data frame. A new column may be a new feature or a copy of an existing column. We'll look at an example in the following exercise. Adding new features can help in improving the efficiency of a model.

Exercise 29: Adding a New Column to an R Data Frame

In this exercise, we will add columns to an existing R data frame. These new columns can be dummy values or copies of other columns.

1. Add a new feature to the R data frame, as follows:

library(caret)

data(GermanCredit)

3. Assign the GermanCredit value to a new field:

#Assign the value to the new field

GermanCredit\$NewField1 <- 1

4. Print the GermanCredit string:

str(GermanCredit)

The output is as follows:

Figure 3.10: Section showing the added NewField
5. Copy an existing column into a new column, as follows:

#Copy an existing column into a new column

GermanCredit\$NewField2 <- GermanCredit...