On 09/01/2014 9:25 AM, Mohammad Tanvir Ahamed wrote:
Hi there !!
I have a matrix like
> mm
[,1] [,2] [,3]
[1,] 1 11 21
[2,] 2 12 22
[3,] 3 13 23
I have a list of position index like
> pos
$row1
[1] 1 3
$row2
[1] 3 2
$row3
[1] 1 3 2
I have a list of values like
> gty
$v1
9 3
$v2
4 8
$v3
7 4 1
Now i want to replace the value of each row in mm by pos list with value gty
> mm
[,1] [,2] [,3]
[1,] 9 11 3
[2,] 8 12 4
[3,] 7 1 4
Any suggestion regarding this problem will be very helpful .
Thank you.
Use matrix indexing. You construct a two column matrix giving the
indices, and then use it as an index to assign a vector of values. In
your case, the matrix should be
1 1
1 3
2 3
2 2
3 1
3 3
3 2
(which you can create as indices <- matrix(c(1,1,1,3, ... ), ncol=2,
byrow = TRUE)
and the vector should be 9 3 4 8 ... . Then
mm[indices] <- vals
will do it.
Duncan Murdoch
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