R: Recipes for Analysis, Visualization and Machine Learning

Chapter 11. Work Smarter, Not Harder – Efficient and Elegant R Code

In this chapter, we will cover recipes for doing the following without explicit iteration:

• Exploiting vectorized operations
• Processing entire rows or columns using the apply function
• Applying a function to all elements of a collection with lapply and sapply
• Applying functions to subsets of a vector
• Using the split-apply-combine strategy with plyr
• Slicing, dicing, and combining data with data tables

Introduction

The R programming language, being procedural, provides looping control structures. Most people will therefore tend to automatically use these control structures in their own code and end up with performance issues because R handles loops very inefficiently. Serious number crunching ...