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.
