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These functions check that packages are installed with minimal side effects. If installed, the packages will be loaded but not attached.

  • is_installed() doesn't interact with the user. It simply returns TRUE or FALSE depending on whether the packages are installed.

  • In interactive sessions, check_installed() asks the user whether to install missing packages. If the user accepts, the packages are installed with pak::pkg_install() if available, or utils::install.packages() otherwise. If the session is non interactive or if the user chooses not to install the packages, the current evaluation is aborted.

You can disable the prompt by setting the rlib_restart_package_not_found global option to FALSE. In that case, missing packages always cause an error.


is_installed(pkg, ..., version = NULL, compare = NULL)

  reason = NULL,
  version = NULL,
  compare = NULL,
  action = NULL,
  call = caller_env()



The package names. Can include version requirements, e.g. "pkg (>= 1.0.0)".


These dots must be empty.


Minimum versions for pkg. If supplied, must be the same length as pkg. NA elements stand for any versions.


A character vector of comparison operators to use for version. If supplied, must be the same length as version. If NULL, >= is used as default for all elements. NA elements in compare are also set to >= by default.


Optional string indicating why is pkg needed. Appears in error messages (if non-interactive) and user prompts (if interactive).


An optional function taking pkg and ... arguments. It is called by check_installed() when the user chooses to update outdated packages. The function is passed the missing and outdated packages as a character vector of names.


The execution environment of a currently running function, e.g. caller_env(). The function will be mentioned in error messages as the source of the error. See the call argument of abort() for more information.


is_installed() returns TRUE if all package names provided in pkg are installed, FALSEotherwise. check_installed() either doesn't return or returns NULL.

Handling package not found errors

check_installed() signals error conditions of class rlib_error_package_not_found. The error includes pkg and version fields. They are vectorised and may include several packages.

The error is signalled with a rlib_restart_package_not_found restart on the stack to allow handlers to install the required packages. To do so, add a calling handler for rlib_error_package_not_found, install the required packages, and invoke the restart without arguments. This restarts the check from scratch.

The condition is not signalled in non-interactive sessions, in the restarting case, or if the rlib_restart_package_not_found user option is set to FALSE.


#> [1] TRUE
is_installed(c("base", "ggplot5"))
#> [1] FALSE
is_installed(c("base", "ggplot5"), version = c(NA, "5.1.0"))
#> [1] FALSE