2 Introduction

The S Programming Language is a statistical programming language developed at Bell Labs “to turn ideas into software, quickly and faithfully” (Chambers 1998).

R is a modern implementation of the S language and part of the GNU Project.

R is an interpreted language, allowing interactive work with data. It is written in C, Fortran, and R itself.

Some of R’s strengths:

The base language (i.e. what is included in R when you first install it) comes loaded with functionality for:
- data cleaning and manipulation
- statistical testing and modeling
- powerful graphics
The vast ecosystem of third party packages brings extensive functionality for statistics, epidemiology, machine learning, visualization, image processing and much more. This includes specialized packages for many biomedical applications.

See also: What is R? on the R Project website.

2.1 Keeping up to date

This book was compiled using R version 4.5.3 (2026-03-11).
Make sure you have the latest version by visiting the R project website.

New versions of R are released regularly and it is a good idea to keep your version of R and installed packages updated.

You can get the version of R currently in use by printing the version object:

version

               _                           
platform       aarch64-apple-darwin20      
arch           aarch64                     
os             darwin20                    
system         aarch64, darwin20           
status                                     
major          4                           
minor          5.3                         
year           2026                        
month          03                          
day            11                          
svn rev        89597                       
language       R                           
version.string R version 4.5.3 (2026-03-11)
nickname       Reassured Reassurer

It’s also a good idea to keep a log of the version of R and installed packages when beginning a new project. An easy way to do this is to save the output of sessionInfo():

sessionInfo()

R version 4.5.3 (2026-03-11)
Platform: aarch64-apple-darwin20
Running under: macOS Tahoe 26.4.1

Matrix products: default
BLAS:   /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib 
LAPACK: /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libRlapack.dylib;  LAPACK version 3.12.1

locale:
[1] C.UTF-8/C.UTF-8/C.UTF-8/C/C.UTF-8/C.UTF-8

time zone: America/Los_Angeles
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

loaded via a namespace (and not attached):
 [1] htmlwidgets_1.6.4 compiler_4.5.3    fastmap_1.2.0     cli_3.6.6        
 [5] tools_4.5.3       htmltools_0.5.9   otel_0.2.0        yaml_2.3.12      
 [9] rmarkdown_2.31    knitr_1.51        jsonlite_2.0.0    xfun_0.57        
[13] digest_0.6.39     rlang_1.2.0       evaluate_1.0.5