Hi:

It's not immediately clear what you have in mind, as others have noted, but
here are a couple of ideas that seem as though they may apply to your
problem, as dangerous as it is to play clairvoyant:

I'm using vectors instead of a matrix, but the first vector, val, contains
the values whereas the second, reps, holds the number of desired
repetitions, which are randomly generated to take values from 1:5.

val <- 1:10
reps <- reps = sample(1:5, 10, replace = TRUE)

(1) Output is a vector:
rep(val, reps)
 [1]  1  1  1  2  2  3  3  3  4  4  4  5  5  5  5  5  6  6  6  6  6  7  7
8  9
[26]  9 10 10 10 10 10

(2) Output is a list:
l <- mapply(rep, val, reps)
> l
[[1]]
[1] 1 1 1

[[2]]
[1] 2 2

[[3]]
[1] 3 3 3

[[4]]
[1] 4 4 4

[[5]]
[1] 5 5 5 5 5

[[6]]
[1] 6 6 6 6 6

[[7]]
[1] 7 7

[[8]]
[1] 8

[[9]]
[1] 9 9

[[10]]
[1] 10 10 10 10 10

Hopefully, one of these answers your question. If not, you'll need to
explain your problem in more detail. The easiest way to do this is to come
up with a toy example, what you tried that didn't work, and the expected
outcome.

Dennis

On Fri, Sep 10, 2010 at 8:54 AM, alfredo <alfredotello@gmail.com> wrote:

>
> Hi Everyone,
>
> I have a 2-dim data.matrix(e.g., table1) in which row1 specifies a range of
> values. row2 - rown specify the number of times I want to replicate each
> corresponding value in row1. I can do this with the following function:
>
> rep(c(table1[1,]),c(table1[X,])) #where X would go from 2 - n.
>
> Now, I can do this manually by changing the values of X and save each
> resulting array/vector in an object, or write a for loop that will iterate
> through the rows and output a new data.matrix in which row1 - rown will
> correspond to the vectors generated by replicating the values of row1 "row2
> - rown" independent times from the original data.matrix with the rep
> function shown above. So far I have been unable to get the for loop right.
>
> Any help will be most appreciated! Thanks beforehand for your help.
>
> Best,
>
> A
> --
> View this message in context:
> http://r.789695.n4.nabble.com/for-loop-help-please-tp2534666p2534666.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
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