can't find the function subtable

Question

I'm learning R using the book, The Art of R Programming. And in chapter 6, the author Matloff used a function called subtable <- function(tbl,subnames), but as I typed this function subtable, it says not find the function, and I googled, find it's in the package extracat, so I installed this package, but as I'm loading this package, library(extracat), an error message came out, saying

library(extracat)
   Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]) : 
   there is no package called ‘plyr’
   Error: package or namespace load failed for ‘extracat’

I can't understand this, how should I use this function? Any suggestions? Much appreciated.

this seems to mean that you need to install the plyr package in order to use the extracat package. So just write install.packages("plyr") and then run: library("extracat") — marbel

Julián Urbano Julián Urbano · Accepted Answer · 2013-12-25T23:50:51

If the book has something like this

subtable <- function(tbl,subnames)

the author is defining a new function called subtable, that receives two parameters called tbl and subnames. The code right below that is what the function runs. I found here and here the function you seem to refer to:

subtable <- function(tbl,subnames) {
   # get array of cell counts in tbl
   tblarray <- unclass(tbl)  
   # we'll get the subarray of cell counts corresponding to subnames by
   # calling do.call() on the "[" function; we need to build up a list
   # of arguments first
   dcargs <- list(tblarray)  
   ndims <- length(subnames)  # number of dimensions 
   for (i in 1:ndims) {
      dcargs[[i+1]] <- subnames[[i]]
   }  
   subarray <- do.call("[",dcargs)  
   # now we'll build the new table, consisting of the subarray, the
   # numbers of levels in each dimension, and the dimnames() value, plus
   # the "table" class attribute
   dims <- lapply(subnames,length) 
   subtbl <- array(subarray,dims,dimnames=subnames)
   class(subtbl) <- "table"
   return(subtbl)
}

Once you write (or copy-paste) all that code in your R console, you'll be able to call this function. So I doubt you want to install any new packages here!

can't find the function subtable

1 Answers