[R] crosstabulation and unlist function

[eugen pircalabelu]

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!

 Eugen Pircalabelu