Installing & Updating Packages in R

This tutorial provides the basics of installing and working with packages in R.

About Packages in R

Packages are collections of R functions, data, and compiled code in a well-defined format. When you install a package it gives you access to a set of commands that are not available in the base R set of functions. The directory where packages are stored is called the library. R comes with a standard set of packages. Others are available for download and installation. Once installed, they have to be loaded into the session to be used.

Installing Packages in R

To install a package you have to know where to get the package. Most established packages are available from "CRAN" or the Comprehensive R Archive Network.

Packages download from specific CRAN "mirrors"" where the packages are saved (assuming that a binary, or set of installation files, is available for your operating system). If you have not set a preferred CRAN mirror in your options(), then a menu will pop up asking you to choose a location from which you'd like to install your packages.

To install any package from CRAN, you use install.packages(). You only need to install packages the first time you use R (or after updating to a new version).

# install the ggplot2 package
install.packages("ggplot2") 

Use a Package

Once a package is installed (basically the functions are downloaded to your computer), you need to "call" the package into the current session of R. This is essentially like saying, "Hey R, I will be using these functions now, please have them ready to go". You have to do this ever time you start a new R session, so this should be at the top of your script.

When you want to call a package, use library(PackageNameHere). You may also see some people using require() -- while that works in most cases, it does function slightly differently and best practice is to use library().

# load the package
library(ggplot2)

What Packages are Installed Now?

If you want to use a package, but aren't sure if you've installed it before, you can check! In code you, can use installed.packages().

# check installed packages
installed.packages()

If you are using RStudio, you can also check out the Packages tab. It will list all the currently installed packages and have a check mark next to them if they are currently loaded and ready to use. You can also update and install packages from this tab. While you can "call" a package from here too by checking the box I wouldn't recommend this as calling the package isn't in your script and you if you run the script again this could trip you up!

Updating Packages

Sometimes packages are updated by the users who created them. Updating packages can sometimes make changes to both the package and also to how your code runs. ** If you already have a lot of code using a package, be cautious about updating packages as some functionality may change or disappear.**

Otherwise, go ahead and update old packages so things are up to date.

In code you, can use old.packages() to check to see what packages are out of date.

update.packages() will update all packages in the known libraries interactively. This can take a while if you haven't done it recently! To update everything without any user intervention, use the ask = FALSE argument.

If you only want to update a single package, the best way to do it is using install.packages() again.

# list all packages where an update is available
old.packages()

# update all available packages
update.packages()

# update, without prompts for permission/clarification
update.packages(ask = FALSE)

# update only a specific package use install.packages()
install.packages("plotly")

In RStudio, you can also manage packages using Tools -> Install Packages.