Efficent way to create an nxn upper triangular matrix of one's
Here is a way to do this: round(upper.tri(matrix(1, 9, 9))) Or if you also need the diagonal of one's round(upper.tri(matrix(1, 9, 9), diag = TRUE)) -Christos
-----Original Message-----
From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org] On Behalf Of Dale Steele
Sent: Wednesday, February 11, 2009 4:23 PM
To: R help
Subject: [R] Efficent way to create an nxn upper triangular
matrix of one's
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
______________________________________________ R-help at 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.