Re: [R] Warning: matrix by vector division

Dear all, Thank you very much for all your valuable suggestions! Best wishes, Alexey Shipunov __ R-help@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.htm

Re: [R] Warning: matrix by vector division

Alexey Shipunov wrote: > Dear list, > > I just made a very simple mistake, but it was hard to spot. And I > think that I should warn other people, because it is probably so > simple to make... > > === R code === > > # Let us create a matrix: > (a <- cbind(c(0,1,1), rep(1,3))) > > # [,1] [

Re: [R] Warning: matrix by vector division

R is working exactly as documented. If you look at how the matrix is stored (column-wise) and then what you are dividing by, you will see that it is doing what you asked (when recycling values): > as.vector(a) [1] 0 1 1 1 1 1 > as.vector(a)/c(2,3) [1] 0.000 0.333 0.500 0.333 0.50

Re: [R] Warning: matrix by vector division

and you might want to check ?prop.table > prop.table(a, 2) [,1] [,2] [1,] 0.0 0.333 [2,] 0.5 0.333 [3,] 0.5 0.333 or even ?sweep (which will be useful for more complex situations) > sweep(a, 2, colSums(a), "/") [,1] [,2] [1,] 0.0 0.333 [2,] 0.5 0.333

[R] Warning: matrix by vector division

Dear list, I just made a very simple mistake, but it was hard to spot. And I think that I should warn other people, because it is probably so simple to make... === R code === # Let us create a matrix: (a <- cbind(c(0,1,1), rep(1,3))) # [,1] [,2] # [1,]01 # [2,]11 # [3,]