Hi all;
Thanks for the responses to my query of how to make tapply into a table
instead of an n-dimensional array. Summary of responses follows:
Peter Dalgaard:
as.data.frame(with(tmp,as.table(tapply(C,list(A=A,B=B),sum))))
Phil Spector wrote:
z = tapply(y,list(var1,var2,var3,var4),sum)
data.frame(do.call('expand.grid',dimnames(z)),y=do.call('rbind',as.list(z)))
Hans Gardfjell:
tmp <-
data.frame(A=sample(LETTERS[1:5],10,replace=T),B=sample(letters[1:5],10,replace=T),C=rnorm(10))
tmp1 <- with(tmp,aggregate(C,list(A=A,B=B),sum))
tmp2 <- expand.grid(A=sort(unique(tmp$A)),B=sort(unique(tmp$B)))
merge(tmp2,tmp1,all.x=T)
hadley wickham:
Well, you can almost do this in with the reshape package:
tmp <-
data.frame(A=sample(LETTERS[1:5],10,replace=T),B=sample(letters[1:5],10,replace=T),C=rnorm(10))
a <- recast(tmp, A + B ~ ., sum)
# see also recast(tmp, A ~ B, sum)
add.all.combinations(a, row="A", cols = "B")
Good thing there are so many code cats around, 'cause we have so darn
many ways to skin 'em. Thanks again to all who took the time to answer!!
-Joseph
--
************************************
Joseph P. LeBouton
Forest Ecology PhD Candidate
Department of Forestry
Michigan State University
East Lansing, Michigan 48824
Office phone: 517-355-7744
email: lebouton at msu.edu
