[R] how to divide each element of a matrix by a specific value per column

[adam_pgsql]

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