Installing a Package from a Download Zip File

When working with R packages, it’s not uncommon to download a package as a zip file. However, this is not the standard packaging of a package source or a Windows binary (i.e., a built package distributed as a .zip). In this article, we’ll explore how to install a package from a download zip file using various methods.

Understanding Package Installation

Before diving into installing packages from zip files, let’s quickly review how R packages are installed. The install.packages() function is used to install packages from CRAN (Comprehensive R Archive Network), which is the official repository for R packages. This function downloads and installs a package from the specified location.

Installing Packages Locally

However, sometimes you need to install packages locally, especially when working with source code or when the package is not available on CRAN. In such cases, you’ll need to extract the zip file, build the package using R CMD build, and then install it using R CMD INSTALL or from within R.

Using `devtools`

One easy way to install packages locally is by using the devtools package. You can use the install_github() function to install a package directly from GitHub.

library("devtools")
install_github("hadley/rvest")

This method eliminates the need for manual installation and simplifies the process.

Extracting Zip Files

When extracting a zip file, you’ll typically want to extract it to a specific directory. You can use the unzip() function in R to achieve this.

setwd("C:/Users/Desktop/")
unzip("rvest-master.zip")
file.rename("rvest-master", "rvest")

This will extract the zip file contents to the current working directory and rename the extracted files to match the original package name.

Building a Package

After extracting the zip file, you’ll need to build it using R CMD build. This command compiles the source code into a tarball that can be installed later.

shell("R CMD build rvest")

This will create a tarball of the package in the current working directory.

Installing from Tarballs

Once you have the built tarball, you can install it using install.packages() with the repos = NULL argument. You may need to specify the file name explicitly, as the version number is merged into the tarball name.

install.packages("rvest_0.2.0.9000.tar.gz", repos = NULL)

You can also use list.files() to find all files with a specific pattern (in this case, files containing “rvest” and “.tar.gz”) and install them.

install.packages(list.files(pattern="rvest*.tar.gz"), repos = NULL)

Troubleshooting Errors

When using the shell() function to execute external commands, you may encounter errors if the command is not found in your shell path. To resolve this issue, you can add R’s installation directory to the PATH environment variable.

Sys.setenv(PATH=paste(R.home("bin"), Sys.getenv("PATH"), sep=";"))

This will ensure that the R CMD build and other related commands are executed correctly.

Conclusion

Installing packages from download zip files can be a bit tricky, but with the right tools and techniques, it’s doable. By using devtools, extracting zip files, building packages, and installing tarballs, you can successfully install packages locally. Remember to troubleshoot errors by ensuring that R is in your shell path, and don’t hesitate to reach out if you have any further questions or need additional assistance.

Example Use Cases

Installing a package directly from GitHub using devtools:

library(“devtools”) install_github(“hadley/rvest”)

* Extracting zip files: 
  ```markdown
setwd("C:/Users/Desktop/")
unzip("rvest-master.zip")
file.rename("rvest-master", "rvest")

Building a package using R CMD build:

shell(“R CMD build rvest”)

* Installing packages from tarballs: 
  ```markdown
install.packages("rvest_0.2.0.9000.tar.gz", repos = NULL)

Last modified on 2024-11-14