On Oct 12, 2009, at 2:36 PM, eugen pircalabelu wrote:

Hello R-users,

My toy example:
aa<-c(1:5)
bb<-c(NA,2,NA,4,5)
cc<-c(1,2,NA,4,NA)
dd<-c("A","B","B","A","C")
df<-data.frame(aa,bb,cc,dd=as.factor(dd))
table(unlist(df[,1:3]))

Can anyone point me to what function let's me do a crosstabulation between table(unlist(df[,1:3])) and df$dd? I want to find out when dd==A (or B, or C) how many times do the values 1, 2 ,3,.. appear in df[,1:3]?
Thank you very much!

One way would be to collect the row sums of those columns first, and then sum by index:

tapply(apply(df[,1:3],1,sum, na.rm=TRUE), df$dd, sum)
 A  B  C
14  9 10

--

David Winsemius, MD
Heritage Laboratories
West Hartford, CT

______________________________________________
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.

Reply via email to