# Preface

This book is written by Remco Bast (MSc Health Sciences) and Martijn Heymans for EpidM (https://www.epidm.nl/nl/). This book serves as an introduction to the R programming language and throughout this book RStudio will be used (almost) fully.

R is a powerful programming language developed mainly for applications in the field of statistics and data analysis. One of the biggest advantages of R is that it is open source, which means that anyone can download and modify the code.

Furthermore, R is free to use and no license is required to use it. R is available for Windows, as well as Unix systems (like Linux) and the Mac. In addition, anyone can contribute to R. Developers can write software and publish it as R packages or libraries. Because this is relatively simple there are more than 10,000 packages that can be easily installed.

Finally, we will not be able to discuss everything about R, but hopefully this will serve as an introduction that will at least teach you the basics of R.

## Notation within this book

The names of functions and libraries are listed as they were published under their original name. Furthermore, this book will contain a lot of R code and these can be recognized by gray text boxes. An example of this is as follows:

```
<- 10
x <- c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) y
```

Furthermore, this book also contains a lot of output and this is nothing more than the result we get back from certain code or functions. Output can be recognized by the fact that it always starts with two fences ##.

`mean(y)`

`## [1] 5.5`