Oops, didn't see Marc's reply. His solution is much more compact. For R 2.11.0 and above, aggregate() now has a formula interface that usually works nicely:
aggregate(Var3 ~ Var1 + Var2, data = d, FUN = table) Var1 Var2 Var3.D Var3.I 1 S1 T1 2 2 2 S2 T1 2 2 3 S1 T2 2 2 4 S2 T2 0 4 Dennis On Thu, May 19, 2011 at 12:29 PM, Dennis Murphy <djmu...@gmail.com> wrote: > Hi: > > The dummy column really isn't necessary. Here's another way to get the > result you want. Let d be the name of your example data frame. > > d <- d[, 1:3] > (dtable <- as.data.frame(ftable(d, row.vars = c(1, 2)))) > Var1 Var2 Var3 Freq > 1 S1 T1 D 2 > 2 S2 T1 D 2 > 3 S1 T2 D 2 > 4 S2 T2 D 0 > 5 S1 T1 I 2 > 6 S2 T1 I 2 > 7 S1 T2 I 2 > 8 S2 T2 I 4 > > An alternative to the reshape() function is the reshape2 package, > which has a function dcast() that allows you to rearrange the data > frame as you desire. > > library(reshape2) > dcast(dtable, Var1 + Var2 ~ Var3) > Using Freq as value column: use value_var to override. > Var1 Var2 D I > 1 S1 T1 2 2 > 2 S1 T2 2 2 > 3 S2 T1 2 2 > 4 S2 T2 0 4 > > > HTH, > Dennis > > On Thu, May 19, 2011 at 2:13 AM, Luma R <rluma1...@gmail.com> wrote: >> Dear all, >> >> I am having trouble creating summary tables using aggregate function. >> >> given the following table: >> >> >> Var1 Var2 Var3 dummy >> S1 T1 I 1 >> S1 T1 I 1 >> S1 T1 D 1 >> S1 T1 D 1 >> S1 T2 I 1 >> S1 T2 I 1 >> S1 T2 D 1 >> S1 T2 D 1 >> S2 T1 I 1 >> S2 T1 I 1 >> S2 T1 D 1 >> S2 T1 D 1 >> S2 T2 I 1 >> S2 T2 I 1 >> S2 T2 I 1 >> S2 T2 I 1 >> >> >> I want to create a summary table that shows for each category of Var1, >> Var2, the number of cells that are Var3=D and Var3-I : >> >> Var1 Var2 Var3(D) Var3(I) >> S1 T1 2 2 >> S1 T2 2 2 >> S2 T1 2 2 >> S2 T2 0 4 >> >> >> >> However, if I do: Count.Cells= aggregate(dummy~ Var1+Var2+Var3, FUN='sum') >> , I get: >> >> Var1 Var2 Var3 Count of Resp >> S1 T1 D 2 >> S1 T1 I 2 >> S1 T2 D 2 >> S1 T2 I 2 >> S2 T1 D 2 >> S2 T1 I 2 >> S2 T2 I 4 >> >> >> Is there a way to get different columns for each Var3 level? >> >> >> Thank you for any help you can give! >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
