R/NAME_check_missing_packages.R

In sebastiansauer/prada: Data and R functions for practical data analysis

#' Check which packages are missing
#'
#' Checks which packages are used in a folder/R project but are not installed locally
#'
#' This function checks which R packages are called by the function `library` in any script file (.r, .rmd, .qmd) in the local working directory. In requested by the user, the missing packages are installed from CRAN. In any case, the difference between the packages callled in the project folder and the packages installed are returned.
#'
#' @param install_missing_packages should missing packages be installed? Defaults to no (lgl)

#' @return string vector of missing packages
#' @export
#'
#' @examples
#' \dontrun{install_missing_packages()}





check_missing_packages <- function(install_missing_packages = FALSE){


  files <- list.files(pattern='[.](R|rmd|qmd)$', all.files=T, recursive=T, full.names = T, ignore.case=T)

  # read in source code:
  code <- unlist(sapply(files, scan, what = 'character', quiet = TRUE))

  # retain only source code starting with library
  code <- code[grepl('^library', code, ignore.case=T)]
  code <- gsub('^library[(]', '', code)
  code <- gsub('[)]', '', code)
  code <- gsub('^library$', '', code)

  # retain unique packages:
  uniq_packages <- unique(code)

  # kick out "empty" package names:
  uniq_packages <- uniq_packages[!uniq_packages == '']

  # order alphabetically:
  uniq_packages <- uniq_packages[order(uniq_packages)]

  cat('Required packages: \n')
  cat(paste0(uniq_packages, collapse= ', '),fill=T)
  cat('\n\n\n')

  # retrieve list of already installed packages:
  installed_packages <- installed.packages()[, 'Package']

  # identify missing packages:
  to_be_installed <- setdiff(uniq_packages, installed_packages)

  if (length(to_be_installed)==length(uniq_packages)) cat('All packages need to be installed.\n')
  if (length(to_be_installed)>0) {
    cat('Some needed packages already exist; some are missing.\n')
    cat("The following packages are missing:\n")
    cat(to_be_installed)
  }
  if (length(to_be_installed)==0) cat('All packages installed already!\n')

  # install missing packages:
  if ((length(to_be_installed)>0) & install_missing_packages) {
    cat("Now installing the missing packages.\n")
    install.packages(to_be_installed, repos = 'https://cloud.r-project.org')
  }
  cat('\nDone!\n\n')

  return(to_be_installed)

}