[R] data manipulation between vector and matrix

[Sarah Goslee]

Hi,

On Wed, Dec 5, 2012 at 1:30 PM, C W <tmrsg11 at gmail.com> wrote:
> Dear list,
> I was curious how to subtract a vector from matrix?
>
> Say, I have
>
> mat <- matrix(1:40, nrow=20, ncol=2)
>
> x <-c(1,2)

Thanks for the actual reproducible example.

> I want,
>
> x-mat[1,] and x-mat[2,], and so on... Basically, subtract column elements
> of x against column elements in mat.
>
> But x-mat won't do it.

This will (note the modification to get x - mat):
> sweep(-mat, 2, x, "+")
      [,1] [,2]
 [1,]    0  -19
 [2,]   -1  -20
 [3,]   -2  -21
 [4,]   -3  -22
 [5,]   -4  -23
etc.

--
Sarah Goslee
http://www.functionaldiversity.org