Data reshaping

res1<- xtabs(X3~X1+X2,data=Dat)
res1
#?? X2
#X1?? 1? 2? 3? 4
?# A 11 12 13 14
?# B 15 16 17 18
?# C 19 20 21? 0
library(reshape2)
?dcast(Dat,X1~X2,value.var="X3")
#? X1? 1? 2? 3? 4
#1? A 11 12 13 14
#2? B 15 16 17 18
#3? C 19 20 21 NA
A.K.


Hello again, let say I have following data-frame:

Dat <- data.frame(c(rep(c("A", "B"), each = 4), "C", "C", "C"), 

c(rep(1:4, 2), 1, 2, 3), 11:21)

colnames(Dat) <- c("X1", "X2", "X3") 
Dat 

? ?X1 X2 X3 
1 ? A ?1 11 
2 ? A ?2 12 
3 ? A ?3 13 
4 ? A ?4 14 
5 ? B ?1 15 
6 ? B ?2 16 
7 ? B ?3 17 
8 ? B ?4 18 
9 ? C ?1 19 
10 ?C ?2 20 
11 ?C ?3 21 


Now I want to put that data-frame in the following form:

Dat1 <- rbind(c(11,12,13,14), c(15,16,17,18), c(19,20,21, NA)); 

colnames(Dat1) <- c(1,2,3,4); rownames(Dat1) <- c("A", "B", "C")

Dat1 

? ?1 ?2 ?3 ?4 
A 11 12 13 14 
B 15 16 17 18 
C 19 20 21 NA 


Basically, 'Dat' is the melted form of 'Dat1' 

Can somebody point me any R function for doing that? 

Thanks for your help.