# Using Use

The renv::use() function can make it easier to define stand-alone R scripts that include their R package requirements directly in the script itself. For example:


# write down the set of packages required by this script
renv::use(
"digest",         # use the latest-available version of digest
"rlang@0.3.4"     # use an older release of rlang (installed from archive)
)

# use the requested packages
digest::digest(list(answer = 42))

Running a script with these contents will:

1. Automatically download the requested packages – in this case, the latest release of digest, alongside rlang 0.3.4,

2. Install the requested packages (plus their recursive package dependencies) to a temporary library path,

3. Activate that library path, so that it’s used subsequently in the script.

renv::use() can hence be a useful way of sharing standalone R scripts with a set of specific package requirements. Running these scripts will ensure the requested packages are automatically downloaded and installed.

In addition, you can also supply the path to a lockfile. For example:


# use a particular lockfile in the context of this script
renv::use(lockfile = "/path/to/renv.lock")

# the rest of this script will run with the packages as declared
# in that lockfile installed into a temporary library path

This can be useful in projects where you’d like to associate different lockfiles with different documents – for example, in a blog or a website where you’d like to associate a separate lockfile with each post. Once the post is complete, you could use renv::snapshot(lockfile = "/path/to/renv.lock") to “save” the state that was active while authoring that lockfile, and then use renv::use(lockfile = "/path/to/renv.lock") in that document to ensure the blog post is always run using that lockfile on future renders.