Installing R Packages from Source: A Comprehensive Guide

Introduction

In data analysis and statistical computing, R is a powerful tool that offers extensive packages to perform various tasks. Sometimes, you may need to install an R package from its source rather than using pre-compiled binaries available on CRAN (Comprehensive R Archive Network). This could be due to the requirement for specific versions or dependencies not met by existing binaries. In this tutorial, we will explore how to install R packages directly from their source code.

Understanding Packages in R

An R package is a collection of functions, datasets, and compiled code in a well-defined format. When you wish to extend R’s capabilities, installing packages is the way forward. Most users download and install these packages using the install.packages() function, which fetches pre-compiled binaries from CRAN or other repositories.

However, if no binary version is available for your platform, or you need a particular version of the package that isn’t on CRAN, installing from source becomes necessary. Source installation involves compiling code written in C, C++, or Fortran along with R scripts.

Prerequisites

Before proceeding to install an R package from its source:

1. Ensure you have R installed. You can download it from The Comprehensive R Archive Network (CRAN).

2. Verify that you have the necessary tools for compilation:

   • On Windows, this might involve installing Rtools.
   • On macOS and Linux, ensure build-essential tools like gcc, make, and others are installed.

3. Some packages may require additional system libraries to be present on your machine.

Installing Packages from a Local Source File

If you have downloaded the source package (usually in .tar.gz format for UNIX-like systems or .zip for Windows), follow these steps:

1. Install via R Console: You can use install.packages() with repos=NULL to specify the path of your local file.

   install.packages("path/to/your/package.tar.gz", repos = NULL, type="source")
   

   Replace "path/to/your/package.tar.gz" with the actual path to your source file. Ensure you use forward slashes / or double backslashes \\ in the path for UNIX-like systems and Windows respectively.

2. Install via Terminal: For macOS and Linux users, this involves using the terminal:

   R CMD INSTALL /path/to/package.tar.gz
   

   Navigate to the directory containing your source file before executing the command.

Installing Packages from a Repository

You can also install packages directly from an online repository using install.packages() with specific parameters:

install.packages("package_name", repos = "https://repository.url/", type="source")

Replace "package_name" with the name of your package and "https://repository.url/" with the URL of the repository where the source file is hosted.

Installing Older Versions or from GitHub

For installing specific older versions of a package, use:

install.packages("http://cran.r-project.org/src/contrib/Archive/package_name/package_version.tar.gz", repos=NULL, type="source")

To install packages directly from GitHub repositories, you can leverage the devtools package:

1. First, install and load devtools if not already installed:

   install.packages("devtools")
   library(devtools)
   

2. Install a package from its GitHub repository:

   devtools::install_github("username/repository_name")
   

Replace "username" with the GitHub username and "repository_name" with the name of the repository.

Conclusion

Installing R packages from source provides flexibility, especially when dealing with version compatibility or system-specific requirements. By following the outlined steps, you can enhance your R environment to include custom or specific versions of necessary packages, thereby tailoring it to meet your analytical needs effectively.