1 2 3 4  5
5 3 2 4  6
2 3 4 5 21
20 2 5 3  2

library(data.table)
options(as.data.table=TRUE)
data <- fread("data.txt", header=FALSE)

dimnames(data)
[[1]]
NULL
[[2]]
[1] "V1" "V2" "V3" "V4" "V5"

dcast(melt(data, id.vars = "col0"), variable ~ col0)