[R] matrix column division by vector

[Jeff Newmiller]

Please post in plain text... your email is getting distorted and hard to read by the HTML.

I don't know how to use do.call for this, but when you understand how vectors recycle and matrices and arrays are laid out in memory (read the Introduction to R document if not) then the following comes to mind:

mat2 <- m / matrix( v, ncol=ncol(m), nrow=nrow(m), byrow=TRUE )

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On May 14, 2014 7:51:36 AM PDT, carol white <wht_crl at yahoo.com> wrote:
>Hi,
>What is the elegant script to divide the columns of a matrix by the
>respective position of a vector elements?
>
>m=rbind(c(6,4,2),c(3,2,1))
>
>v= c(3,2,1)
>
>res= 6/3�� 4/2� 2/1
>������� 3/3�� 2/2 �� 1/1
>
>
>this is correct�
>mat2 = NULL
>
>for (i in 1: ncol(m))
>
>��� mat2 = cbind(mat2, m[,i]/ v[i])
>
>
>but how to do more compact and elegant with for ex do.call?
>
>Many thanks
>
>Carol
>	[[alternative HTML version deleted]]
>
>
>
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