Perhaps:
b[1:nrow(d), 2:3] <- b[1:nrow(d), 2:3]+d
For seconde questin you can use the which function.
which(b==5, arr.ind=T)
On 23/10/2007, Rainer M Krug <[EMAIL PROTECTED]> wrote:
>
> Hi
>
> I have another question concerning matrices:
> I have two matrices:
>
> > b <- matrix(1:25,5,5,byrow=T)
> > b
> [,1] [,2] [,3] [,4] [,5]
> [1,] 1 2 3 4 5
> [2,] 6 7 8 9 10
> [3,] 11 12 13 14 15
> [4,] 16 17 18 19 20
> [5,] 21 22 23 24 25
>
> and
>
> > d <- matrix(1:4,2,2,byrow=T)
> > d
> [,1] [,2]
> [1,] 1 2
> [2,] 3 4
> >
>
>
> and I want to "add" d to b in such a way that I specify one cell in
> matrix b , e.g. [1,2]:
>
>
> [,1] [,2] [,3] [,4] [,5]
> [1,] 1 2+1 3+2 4 5
> [2,] 6 7+3 8+4 9 10
> [3,] 11 12 13 14 15
> [4,] 16 17 18 19 20
> [5,] 21 22 23 24 25
>
> Is there an easy way of doing this, apart from iterating through the
> matrix d?
>
> Also, when I use
>
> > apply(d, c(1,2), function(x) {})
>
> is there a way of knowing the column anr row which the element x is
> from, or o I have to use for loops for that?
>
> Thanks in advance,
>
> Rainer
>
> ______________________________________________
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
>
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
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