[R] Efficent way to create an nxn upper triangular matrix of one's

[Dale Steele]

The code below create an nxn upper triangular matrix of one's.  I'm
stuck on finding a more efficient vectorized way - Thanks.  --Dale

n <- 9
data <- matrix(data=NA, nrow=n, ncol=n)
data
for (i in 1:n) {
    data[,i] <- c(rep(1,i), rep(0,n-i))
}
data