function that reports the names and version numbers of packages in an R workspace

get_pkg_versions.R

#' Retrieve attached or loaded package names and their version numbers
#'
#' @param L an object of class 'sessionInfo'. Default is to retrieve the current
#'     workspace session information.
#' @param n character specifying whether to use attached packages ('otherPkgs') or
#'     packages only loaded via a namespace ('loadedOnly'). Base packages are always
#'     omitted.
#'
#' @return a data frame with two columns: the package name and the package version number.
#' @export
#'
#' @examples
#' get_pkg_versions()
#' get_pkg_versions()

get_pkg_versions <- function(L = sessionInfo(), n = c("basePkgs", "otherPkgs", "loadedOnly")) {
  n <- match.arg(n)
  if (n == "basePkgs") {
    data.frame(name = L[[n]], version = with(R.version, paste(major, minor, sep = ".")))
  } else {
    vers <- unname(sapply(L[[n]], function(x) x[["Version"]]))
    pkg <- unname(sapply(L[[n]], function(x) x[["Package"]]))
    data.frame(name = pkg, version = vers)
  }
}