Getting a list of functions and objects in a package

Problem

You want to find out what’s in a package.

Solution

This code snippet will list the functions and objects in a package.

  1. # Using search() in a new R session says that these packages are 
  2. # loaded by default:
  3. # "package:stats"     "package:graphics" 
  4. # "package:grDevices" "package:utils"     "package:datasets" 
  5. # "package:methods"   "package:base"  
  7. # Others that are useful:
  8. # gplots
  9. # ggplot2, reshape, plyr
  11. showPackageContents <- function (packageName) {
  13.     # Get a list of things contained in a particular package
  14.     funlist <- objects(packageName)
  16.     # Remove things that don't start with a letter
  17.     idx <- grep('^[a-zA-Z][a-zA-Z0-9._]*', funlist)
  18.     funlist <- funlist[idx]
  20.     # Remove things that contain arrow <-
  21.     idx <- grep('<-', funlist)
  22.     if (length(idx)!=0)
  23.         funlist <- funlist[-idx]
  25.     # Make a data frame to keep track of status
  26.     objectlist <- data.frame(name=funlist,
  27.                              primitive=FALSE,
  28.                              func=FALSE,
  29.                              object=FALSE,
  30.                              constant=FALSE,
  31.                              stringsAsFactors=F)
  33.     for (i in 1:nrow(objectlist)) {
  34.         fname <- objectlist$name[i]
  35.         if (exists(fname)) {
  36.             obj <- get(fname)
  37.             if (is.primitive(obj)) {
  38.                 objectlist$primitive[i] <- TRUE
  39.             }
  40.             if (is.function(obj)) {
  41.                 objectlist$func[i] <- TRUE
  42.             }
  43.             if (is.object(obj)) {
  44.                 objectlist$object[i] <- TRUE
  45.             }
  47.             # I think these are generally constants
  48.             if (is.vector(obj)) {
  49.                 objectlist$constant[i] <- TRUE
  50.             }
  53.         }  
  54.     }
  56.     cat(packageName)
  58.     cat("\n================================================\n")
  59.     cat("Primitive functions: \n")
  60.     cat(objectlist$name[objectlist$primitive])
  61.     cat("\n")
  63.     cat("\n================================================\n")
  64.     cat("Non-primitive functions: \n")
  65.     cat(objectlist$name[objectlist$func  &  !objectlist$primitive])
  66.     cat("\n")
  68.     cat("\n================================================\n")
  69.     cat("Constants: \n")
  70.     cat(objectlist$name[objectlist$constant])
  71.     cat("\n")
  73.     cat("\n================================================\n")
  74.     cat("Objects: \n")
  75.     cat(objectlist$name[objectlist$object])
  76.     cat("\n")
  77. }
  80. # Run the function using base package
  81. showPackageContents("package:base")