Install an R package temporarily, only for the current session - r

Question

Sometimes on Stack Overflow, there's a question relative to a package which is not installed on my system, and which I don't plan to reuse later.
If I install the package with install.packages(), it will be put in one of my R install libraries, and then will take some storage space and be updated each time I run update.packages().
Is there a way to install a package only for the current R session ?

Answer 1

You can install a package temporarily with the following function :
tmp.install.packages <- function(pack, dependencies=TRUE, ...) {
path <- tempdir()
## Add 'path' to .libPaths, and be sure that it is not
## at the first position, otherwise any other package during
## this session would be installed into 'path'
firstpath <- .libPaths()[1]
.libPaths(c(firstpath, path))
install.packages(pack, dependencies=dependencies, lib=path, ...)
}
Which you can use simply this way :
tmp.install.packages("pkgname")
The package is installed in a temporary directory, and its files should be deleted at next system restart (at least on linux systems).

Answer 2

Another solution for this problem is devmode from devtools. Devmode allows you to install packages to a dev repository so your other packages are untouched if you install development versions. For example:
library(devtools)
devmode()
install_github('ggplot2', 'hadley')
devmode()
You'll notice that your version has not changed.

Answer 3

pacman deals with package management issues like this:
library(pacman)
Now you can use:
p_load("pkgname") #installs or loads package if already installed
#at end of session:
p_delete("pkgname") #deletes package from lib
This is a quick way to install in your directory and then delete it at the end (not really a temporary install)

Answer 4

As an addition to Tyler's answer a p_temp function was recently added to the pacman package which does exactly what the question asks for.
library(pacman)
p_temp(pkgname) # or p_temp("pkgname") either work...
This will install the package and any dependencies temporarily.
Disclosure: Tyler and I are co-authors of the pacman package...

Answer 5

The following is something in the middle between
juba
and
sebastian-c,
and is as simple as that:
.libPaths("/my/path")
Now and until the end of the current session,
you can install packages as you normally would, and they will end up in
/my/path.
Also package dependencies will go to /my/path.
If you want to have control over dependencies, you can specify them manually with:
install.packages(c("pack", "dep1", "dep2", ...), dependencies = FALSE)
This approach might be useful in two particular scenarios:
A so-to-say discovery session. You want to discover new packages and install them casually to see if something interesting pops up. Then, you use an OS provided tempdir in .libPaths(), to avoid messing your R setup, and the OS will take care of the cleaning.
Create, nowadays common, reproducible environments.
You install a base R, then add .libPaths("my/project/dir"). By looking at this dir, you have a clear picture of what are your project package requirements. Further, you can copy this folder to another PC to reproduce the same environment. Much like Python pipenv you can have more isolated environments: for each session, you call .libPaths() with the related project dir.