Writing Your First R Package

Repository for the 2025 ICA Pre-Conference Hackathon Breakout Session

Prerequisites

• You can code in R
• You know (more or less) how to define a function

Reading

Wickham, H., & Bryan, J. (2023). R Packages: Organize, Document, and Share Your Code. O'Reilly Media. Link: https://r-pkgs.org/

What you need to do

Install the life-saving packages

install.packages(devtools)
install.packages(usethis)

Create a R Project

usethis::create_package("myfirstpkg")

Have at least one function

get_sd <- function(x){
  stats::sd(x)
}

Documentations

Heres are some useful functions to have, I will explain it later...

usethis::use_mit_license()
usethis::use_package("stats")
devtools::document()

Setup a Git Repository

Again, some useful functions:

usethis::use_git()
usethis::gh_token_help()
usethis::create_github_token()
gitcreds::gitcreds_set()

Create first release

If you follow the steps, you would have written your first package. Seriously, it is that simple.

usethis::use_release_issue()

Install your package

You could use the follow code to install (before putting it on CRAN)

devtools::install_github("justinchuntingho/myfirstpkg")

What's next?

• Readme
• Vignette
• Unit tests
• Bug reports
• Get good at Git (optional, but seriously you would thank yourself in the future)
• Get good at R (optional, but very useful. For example this: https://adv-r.hadley.nz/index.html)
• Write a software paper (for example, Journal of Open Source Software)