Is there something like requirements.txt for R?

Question

Is there a functionality like requirements.txt in Python, where you can store a list of packages used into a file, and whenever other people want to run your programs and need to install the dependencies, they can just do pip install -r requirements.txt.

I think, this helps a lot when deploying R script into production. If there is no such functionality, how do I replicate it?

Answer 1

As per the comments, you might want to look at building a package, and including the requirements in the DESCRIPTION file. If you're talking about putting a .R script "into production", you can put a function at the start to make sure the packages required are installed. Here's something along those lines that I have in my own package, and I can call pkgLoad( <list of packages> ) at the beginning of any script to make sure the packages are installed and loaded. I include a list of my favourite packages, such that a call of pkgLoad() installs and loads all my usual suspects:

pkgLoad <- function( packages = "favourites" ) {

    if( length( packages ) == 1L && packages == "favourites" ) {
        packages <- c( "data.table", "chron", "plyr", "dplyr", "shiny",
                       "shinyjs", "parallel", "devtools", "doMC", "utils",
                       "stats", "microbenchmark", "ggplot2", "readxl",
                       "feather", "googlesheets", "readr", "DT", "knitr",
                       "rmarkdown", "Rcpp"
        )
    }

    packagecheck <- match( packages, utils::installed.packages()[,1] )

    packagestoinstall <- packages[ is.na( packagecheck ) ]

    if( length( packagestoinstall ) > 0L ) {
        utils::install.packages( packagestoinstall,
                             repos = "http://cran.csiro.au"
        )
    } else {
        print( "All requested packages already installed" )
    }

    for( package in packages ) {
        suppressPackageStartupMessages(
            library( package, character.only = TRUE, quietly = TRUE )
        )
    }

}

Note I've built my favourite CRAN mirror into the function, so make sure you edit that for your own needs.