Try this: sweep(y, 2, x, "/")
On Thu, Jan 27, 2011 at 1:18 PM, adam_pgsql <adam_pg...@witneyweb.org>wrote: > > Hi, > > I'd like to divide each element of a matrix by a specific value per column. > These specific values are stored in a list. For example: > > > x <- c(1,2,3,4,5) > > y <- matrix(c(1:30), nrow = 6) > > Now I want to divide each element in y[,1] by x[1], y[,2] by x[2] etc. I > have tried this > > > my_function <- function(data, ind) data/ind > > apply(y, 2, my_function, x) > [,1] [,2] [,3] [,4] [,5] > [1,] 1 7.0 13.0 19.0 25.0 > [2,] 1 4.0 7.0 10.0 13.0 > [3,] 1 3.0 5.0 7.0 9.0 > [4,] 1 2.5 4.0 5.5 7.0 > [5,] 1 2.2 3.4 4.6 5.8 > [6,] 6 12.0 18.0 24.0 30.0 > Warning messages: > 1: In data/ind : > longer object length is not a multiple of shorter object length > 2: In data/ind : > longer object length is not a multiple of shorter object length > 3: In data/ind : > longer object length is not a multiple of shorter object length > 4: In data/ind : > longer object length is not a multiple of shorter object length > 5: In data/ind : > longer object length is not a multiple of shorter object length > > but as you can see it is applying them by row rather than column. Any ideas > how to do this? Is there a variable within 'apply' that can be used to > determine which column of y is being processed? > > thanks for any help > > adam > > > sessionInfo() > R version 2.11.1 (2010-05-31) > x86_64-apple-darwin9.8.0 > > locale: > [1] en_GB.UTF-8/en_GB.UTF-8/C/C/en_GB.UTF-8/en_GB.UTF-8 > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > ______________________________________________ > 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.html > and provide commented, minimal, self-contained, reproducible code. > -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O [[alternative HTML version deleted]]
______________________________________________ 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.html and provide commented, minimal, self-contained, reproducible code.
