[R] is there a way to let R do smart matrix-vector operation?

[Robin Hankin]

One can always use the often-overlooked sweep():


 > a <- matrix(2:7,2,3)
 > b <- matrix(1:2,2,1)
 > sweep(a,1,b)
      [,1] [,2] [,3]
[1,]    1    3    5
[2,]    1    3    5
 >

best


rksh



On 6 Mar 2006, at 23:10, Michael wrote:

> Hi all,
>
> I want to substract vector B from A's each column... how can R do that
> smartly without a loop?
>
>> A=matrix(c(2:7), 2, 3)
>> A
>      [,1] [,2] [,3]
> [1,]    2    4    6
> [2,]    3    5    7
>> B=matrix(c(1, 2), 2, 1)
>> B
>      [,1]
> [1,]    1
> [2,]    2
>> A-B
> Error in A - B : non-conformable arrays
>
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--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre, Southampton
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