Hello,
Take advantage that in R '*' recycles its arguments (the shorter one)
and that the operation is performed column-wise:
t(y * t(x))
Hope this helps,
Rui Barradas
Em 03-11-2016 21:05, Dimitri Liakhovitski escreveu:
Hello!
I have a matrix x and a vector y:
x <- matrix(1:6, ncol = 2)
y <- c(2,3)
I need to multiply the first column of x by 2 (y[1]) and the second
column of x by 3 (y[2]).
Of course, I could do this - but it's column by column:
x[,1] <- x[,1] * y[1]
x[,2] <- x[,2] * y[2]
x
Or I could repeat each element of y and multiply two matrices - that's better:
rep.row<-function(x,n){
matrix(rep(x,each=n),nrow=n)
}
y <- rep.row(y, nrow(x))
x * y
However, maybe there is a more elegant r-like way of doing it?
Thank you!
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