[R] Element-by-element operation (adding)

[Peter Langfelder]

Two solutions...

v + matrix(b, nrow(v), ncol(v), byrow = TRUE)

or

t(apply(v, 1, `+`, b))

Peter

On Sun, May 22, 2016 at 10:39 PM, Steven Yen <syen04 at gmail.com> wrote:
> Hi all, need help below. Thank you.
>
>  > # Matrix v is 5 x 3
>  > # Vector b is of length 3
>  > # I like to add b[1] to all element in v[,1]
>  > # I like to add b[2] to all element in v[,2]
>  > # I like to add b[3] to all element in v[,3]
>  > # as follows
>  > v<-matrix(0,nrow=5,ncol=3); v
>       [,1] [,2] [,3]
> [1,]    0    0    0
> [2,]    0    0    0
> [3,]    0    0    0
> [4,]    0    0    0
> [5,]    0    0    0
>  > b<-c(0.1,0.2,0.3)
>  > cbind(
> + (b[1]+v[,1]),
> + (b[2]+v[,2]),
> + (b[3]+v[,3]))
>       [,1] [,2] [,3]
> [1,]  0.1  0.2  0.3
> [2,]  0.1  0.2  0.3
> [3,]  0.1  0.2  0.3
> [4,]  0.1  0.2  0.3
> [5,]  0.1  0.2  0.3
>  > # I am obviously not using sapply correctly:
>  > as.data.frame(sapply(b,"+",v))
>      V1  V2  V3
> 1  0.1 0.2 0.3
> 2  0.1 0.2 0.3
> 3  0.1 0.2 0.3
> 4  0.1 0.2 0.3
> 5  0.1 0.2 0.3
> 6  0.1 0.2 0.3
> 7  0.1 0.2 0.3
> 8  0.1 0.2 0.3
> 9  0.1 0.2 0.3
> 10 0.1 0.2 0.3
> 11 0.1 0.2 0.3
> 12 0.1 0.2 0.3
> 13 0.1 0.2 0.3
> 14 0.1 0.2 0.3
> 15 0.1 0.2 0.3
>
>
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>
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