Book Image

Learning R Programming

By : Kun Ren
Book Image

Learning R Programming

By: Kun Ren

Overview of this book

R is a high-level functional language and one of the must-know tools for data science and statistics. Powerful but complex, R can be challenging for beginners and those unfamiliar with its unique behaviors. Learning R Programming is the solution - an easy and practical way to learn R and develop a broad and consistent understanding of the language. Through hands-on examples you'll discover powerful R tools, and R best practices that will give you a deeper understanding of working with data. You'll get to grips with R's data structures and data processing techniques, as well as the most popular R packages to boost your productivity from the offset. Start with the basics of R, then dive deep into the programming techniques and paradigms to make your R code excel. Advance quickly to a deeper understanding of R's behavior as you learn common tasks including data analysis, databases, web scraping, high performance computing, and writing documents. By the end of the book, you'll be a confident R programmer adept at solving problems with the right techniques.
Table of Contents (21 chapters)
Learning R Programming
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

Conditional expressions


It is common that the logic of a program is not perfectly sequential but contains several branches dependent on certain conditions. Therefore, one of the most basic constructs of a typical programming language is its conditional expressions. In R, if can be used to branch the logic flow by logical conditions.

Using if as a statement

Like many other programming languages, the if expression works with a logical condition. In R, a logical condition is represented by an expression producing a single-element logical vector. For example, we can write a simple function check_positive that returns 1 if a positive number is provided and nothing otherwise:

check_positive <- function(x) { 
  if (x > 0) { 
    return(1) 
  } 
} 

In the preceding function, x > 0 is the condition to check. If the condition is satisfied, then the function returns 1. Let's verify the function with various inputs:

check_positive(1)
## [1] 1
check_positive(0...