System.file and nzchar approach, knowing that it is not without issues. If you do not want to load any packages you might want to go with the Nzchar approach, knowing very well that this does not ensure that thereĪre no dependency issues or that the package can be loaded. Whether something is available I would probably go with the system.file and

If you need to use many packages a mixed approach between calling theĮssential things using library and checking whether the rest is availableĪnd then using the :: operator might be a good approach. Giving a cut-off value for how few qualify as few isĭifficult as you also might want to consider whether this is a packageĮxporting just two functions or something extensive like Hmisc or dplyr. If you only need to load a few packages using library to load them all So, this probably is not the right way to go either.Īs we can see there is no one best way to check whether an R package isĪvailable, but depending on the situation you might want to choose one of It will be slow when thousands of packages are installed, so do not use it to find out if a named package is installed (use find.package or system.file) nor to find out if a package is usable (call requireNamespace or require and check the return value) nor to find details of a small number of packages (use packageDescription). Returning the information from installed.packages() is rather slow. The major downside when trying to find whether a package is installed is that # 'License_is_FOSS' 'License_restricts_use' Packages, not only containing names, but also licences, versions, dependencies Calling installed.packages() returns a detailed data frame about installed

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