Check for presence of a package

This function efficiently checks for the presence of a package without loading it (unlike library() or require(). This is useful to force yourself to use the package::function() syntax for addressing functions; you can make sure required packages are installed, but their namespace won't attach to the search path.

Usage

checkPkgs(
  ...,
  install = FALSE,
  load = FALSE,
  repos = "https://cran.rstudio.com"
)

Arguments

...

A series of packages. If the packages are named, the names are the package names, and the values are the minimum required package versions (see the second example).

install

Whether to install missing packages from repos.

load

Whether to load packages (which is exactly not the point of this function, but hey, YMMV).

repos

The repository to use if installing packages; default is the RStudio repository.

Value

Invisibly, a vector of the available packages.

Examples

# \donttest{
squids::checkPkgs('base');

### Require a specific version
squids::checkPkgs(squids = "25.13.1");
#> Error in squids::checkPkgs(squids = "25.13.1"): Of package(s) 'squids', you need at least versions 25.13.1, respectively. Install those with:
#> 
#>   install.packages(c('squids'));

### This will show the error message
tryCatch(
  squids::checkPkgs(
    base = "99",
    stats = "42.5",
    squids = 100
  ),
  error = print
);
#> <simpleError in squids::checkPkgs(base = "99", stats = "42.5", squids = 100): Of package(s) 'base', 'stats' & 'squids', you need at least versions 99, 42.5 & 100, respectively. Install those with:
#> 
#>   install.packages(c('base', 'stats', 'squids'));
#> >
# }