Building an R package

A package can be seen as a coherent group of functions available for future projects. Building your own package enables you to reuse and share your statistical procedures. Function parameters and examples can be documented with Roxygen to facilitate digging back into the code later on. I created my second package  based on instructions from Hadley. My package structure is composed of the following folders:

• R/   contains R code
• test/  contains tests
• inst/  contains files that will be exported with the package
• docs/  contains .Rmd documents illustrating code development steps and data analysis.
• data/    contains data sets exported with the package
• data-raw/    contains raw dataset and R code to extract raw data from disk and from web resources.

Code

Create a directory containing a package skeleton

devtools::create("packagename")

RStudio has a menu build / configure build tools where devtools package functions and document generation can be linked to keyboard shortcuts:

• document CTRL + SHIFT + D 
• build and reload CTRL + SHIFT + B

devtools::load_all() or Cmd + Shift + L, reloads all code in the package.
Add packages to the list of required packages devtools::use_package("dplyr") devtools::use_package("ggplot2", "suggests")

Data

For data I followed his recommendations in r-pkgs/data.rmd devtools::use_data(mtcars) devtools::use_data_raw() # Creates a data-raw/ folder and add it to .Rbuildignore

Tests

Example of testing for the devtools package

Bash command to build and check a package

Bash command to build a package directory:

R CMD build packagename

Bash command to check a package tarball:

R CMD check packagename_version.tar.gz

 An error log (good luck for understanding it) is visible at:

packagename.Rcheck/00check.log

Generate the documentation and check for documentation specific errors

R CMD Rd2pdf tradeflows --no-clean

The --no-clean option keeps among other files a temporary Latex which can be inspected under:

packagename.Rcheck/packagename-manual.tex

Alternatively the build and check procedure can be run in RStudio as explained above.