1.3 What you will get out of this book

This book delivers the knowledge that I think an advanced R programmer should possess: a deep understanding of the fundamentals coupled with a broad vocabulary that means that you can tactically learn more about a topic when needed.

After reading this book, you will:

• Be familiar with the foundations of R. You will understand complex data types and the best ways to perform operations on them. You will have a deep understanding of how functions work, you’ll know what environments are, and how to make use of the condition system.

• Understand what functional programming means, and why it is a useful tool for data science. You’ll be able to quickly learn how to use existing tools, and have the knowledge to create your own functional tools when needed.

• Know about R’s rich variety of object-oriented systems. You’ll be most familiar with S3, but you’ll know of S4 and R6 and where to look for more information when needed.

• Appreciate the double-edged sword of metaprogramming. You’ll be able to create functions that use tidy evaluation, saving typing and creating elegant code to express important operations. You’ll also understand the dangers and when to avoid it.

• Have a good intuition for which operations in R are slow or use a lot of memory. You’ll know how to use profiling to pinpoint performance bottlenecks, and you’ll know enough C++ to convert slow R functions to fast C++ equivalents.