Find package dependencies in R source files and optionally try to install them

FindDependencies.R

# This function finds all "require" and "library" statements within a
# directory tree of R code and optionally attempts to install them as
# quietly as possible.
# Usage: setwd("yourcodedirectory"); FindDependencies()
# To install required packages if not currently available, run
# FindDependencies(install=T).

FindDependencies <- function(install=F) {
  files <- dir(pattern="\\.R$|\\.S$|\\.r$|\\.s$", recursive=T)
  dependencies <- c()
  for (i in files) {
    f <- suppressWarnings(readLines(i))
    dep <- f[grep("require|library", tolower(f))]
    dep <- gsub("require|library|\\(|\\)| |\\\t", "", dep)
    dependencies <- c(dependencies, dep)
  }
  dependencies <- unique(dependencies)
  cat("Required packages:\n",paste(dependencies, collapse="\n"), "\n")

  if(install) {
    for(i in dependencies) {
      if(!suppressWarnings(require(i, character.only=T))) {
        suppressWarnings(install.packages(i))
        if(!suppressWarnings(require(i, character.only=T)))
          cat("Could not install package", i, "\n")
      }
    }
  }
}