This will create a list of the matrix subsets:
# create a matrix
x <- cbind(1:40, runif(40))
index <- c(10,15,33,40) # cut points
# create a matrix with start and end points
slices <- cbind(start=head(c(1,index + 1), -1), end=index)
# create a list with the matrices
matrix.subset <- lapply(seq(nrow(slices)), function(.row){
x[slices[.row, 1]:slices[.row, 2], ]
})
matrix.subset
On 6/18/07, H. Paul Benton <[EMAIL PROTECTED]> wrote:
>
> Dear All,
>
>
> I have a matrix with data that is not organised. I would like to go
> through this and extract it. Each feature has 2 vectors which express
> the data. I also have an index of the places where the data should be cut.
> eg.
> >class(cc)
> "matrix"
> >cc
> [,1] [,2]
> [1,] 1 26
> [2,] 2 27
> [3,] 3 28
> [4,] 4 29
> [5,] 5 30
> [6,] 6 31
> [7,] 7 32
> [8,] 8 33
> [9,] 9 34
> [10,] 1 27
> [11,] 1 28
> [12,] 2 30
> [13,] 3 34
> ect......
> > index
> [1] "10" "40"
>
>
> Is there a way to take cc[i:index[i-1],] to another format as to where
> each block could be worked on separately. ie so in one block would be
> rows1:10 the next block would be rows11:40 and so on.
>
> Thanks,
>
> Paul
>
>
>
> --
> Research Technician
> Mass Spectrometry
> o The
> /
> o Scripps
> \
> o Research
> /
> o Institute
>
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem you are trying to solve?
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