[R] Element-by-element division

[Steven Yen]

I need help with element-by-element division. Below, matrices a and c are
both 5 x 2 and element-by-element division works as (I) expected. What if
matrix is 1 by 2: to divide first column of a by b[1] and second column of
a by b[2]. I had to go around (two ways) to make it work. In Gauss, these
can be dine by a./b and a./c. Any such simple way in R? Thank!

> a<-matrix(1:10,nrow=5); a
     [,1] [,2]
[1,]    1    6
[2,]    2    7
[3,]    3    8
[4,]    4    9
[5,]    5   10
> b<-matrix(c(0.5,0.25),nrow=1); b
     [,1] [,2]
[1,]  0.5 0.25
> c<-matrix(rep(c(0.5,0.25),5),nrow=5,byrow=T); c
     [,1] [,2]
[1,]  0.5 0.25
[2,]  0.5 0.25
[3,]  0.5 0.25
[4,]  0.5 0.25
[5,]  0.5 0.25

> one<-a/c; one     [,1] [,2]
[1,]    2   24
[2,]    4   28
[3,]    6   32
[4,]    8   36
[5,]   10   40


> two<-a/b
Error in a/b : non-conformable arrays
> two<-cbind(a[,1]/b[1],a[,2]/b[2]); two
     [,1] [,2]
[1,]    2   24
[2,]    4   28
[3,]    6   32
[4,]    8   36
[5,]   10   40

> b2<-matrix(rep(b,5),nrow=5,byrow=T); b2     [,1] [,2]
[1,]  0.5 0.25
[2,]  0.5 0.25
[3,]  0.5 0.25
[4,]  0.5 0.25
[5,]  0.5 0.25> a/b2     [,1] [,2]
[1,]    2   24
[2,]    4   28
[3,]    6   32
[4,]    8   36
[5,]   10   40

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