Hi,

I am trying to reproduce some functionalities of Excel pivot table in R,
sadly, I couldn't figure out how to do it. I am wondering if this is even
possible in R. Does anyone know?

Here is an example:

year=rep(2003,16)
quarter=rep(1:4,each=4)
sales=1:16
company=rep(c("a","b","c","d"),4)
df=data.frame(year,quarter,sales,company) #this is the database

I would like to construct a cross tabulation table like this:
  2003           #a row of year(s)
   1   2   3   4 #a row of quarters of each year
a 1   2   3   4
b 5   6   7   8
c 9  10  11 12
c 13 14 15 16
                     #maybe add a row of subtotal for each quarter at the
end.

I tried xtabs, but all I could produce is this, unfortunately:
 xtabs(sales~year+quarter, data=df)
      quarter
year    1  2  3  4
  2003 10 26 42 58

or this:


 xtabs(sales~year+quarter+company, data=df)
, , company = a

      quarter
year    1  2  3  4
  2003  1  5  9 13

, , company = b

      quarter
year    1  2  3  4
  2003  2  6 10 14

, , company = c

      quarter
year    1  2  3  4
  2003  3  7 11 15

, , company = d

      quarter
year    1  2  3  4
  2003  4  8 12 16
Thanks!

-- 
Tom

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