Check if R package is installed then load library

Question

Our R scripts are used on multiple users on multiple computers and hence there are deviations in which packages are installed on each computer. To ensure that each script wo

Answer 1

I wrote this function the other day that I thought would be useful...

install_load <- function (package1, ...)  {   

   # convert arguments to vector
   packages <- c(package1, ...)

   # start loop to determine if each package is installed
   for(package in packages){

       # if package is installed locally, load
       if(package %in% rownames(installed.packages()))
          do.call('library', list(package))

       # if package is not installed locally, download, then load
       else {
          install.packages(package)
          do.call("library", list(package))
       }
   } 
}