I have spent some time now learning RESHAPE2 and plyr but I still do not get it. This time I have a problem with (a) subtotals and (b) passing different aggregate functions . Here an example using data from the excellent tutorial on the blog of mrdwab http://news.mrdwab.com/

 # libraries 
   library(plyr)
   library(reshape2)
  # get data and add few more variables 
  book.sales = read.csv("http://news.mrdwab.com/data-booksales")
  book.sales$Stock = book.sales$Quantity + 10
  book.sales$SubjCat[(book.sales$Subject == 'Economics') | (book.sales$Subject == 'Management') ] <- '1_EconSciences'
  book.sales$SubjCat[book.sales$Subject %in%  c('Anthropology', 'Politics', 'Sociology') ]        <- '2_SocSciences'
  book.sales$SubjCat[book.sales$Subject %in% c('Communication', 'Fiction', 'History', 'Research', 'Statistics') ]   <- '3_other'

  # to get to my starting dataframe (close to the project I am working on) 
    book.sales1 <- ddply(book.sales, c('Region', 'Representative', 'SubjCat', 'Subject', 'Publisher'), summarize,
                             Stock  =  sum(Stock),
                             Sold   =  sum(Quantity),
                             Ratio  =  round((100 * sum(Quantity)/ sum(Stock)), digits = 1))


 #melt it 
 m.book.sales = melt(data = book.sales1, 
                id.vars = c('Region', 'Representative', 'SubjCat', 'Subject', 'Publisher'),
                measured.vars = c('Stock', 'Sold', 'Ratio'))



  # cast it 
   Tab1 <- dcast(data = m.book.sales, 
          formula = Region + Representative ~ Publisher + variable,
          fun.aggregate = sum,
          margins = c('Region', 'Representative'))

Now my questions :

1. I have been able to add the subtotals in rows. But is it possible also to add margins in the columns. Say for example, Totals of Stock for one Publisher ? Sorry I meant to say example total sold for all publishers

2. There is a problem with the columns with “ratio”. How can I get “mean” instead of “sum” for this variable ?

P.S: I have seen some examples using reshape. Will you recommend to use it instead of reshape2 (which seems not to include the functionalities of two functions).