[R] How to count the number of sequences in matrix?

[Dimitris Rizopoulos]

one approach is the following:

res <- apply(g, 1, function (x) {
    out <- rle(as.logical(x))
    out <- out$lengths[out$values]
    ln <- length(out)
    c(rep(ln, ln), out)
})

cbind(rep(1:nrow(g), sapply(res, length) / 2),
    do.call("rbind", sapply(res, matrix, ncol = 2)))


I hope it helps.

Best,
Dimitris


----- Original Message ----- 
From: "Lauri Nikkinen" <lauri.nikkinen at iki.fi>
To: <r-help at stat.math.ethz.ch>
Sent: Tuesday, November 13, 2007 2:07 PM
Subject: [R] How to count the number of sequences in matrix?


> Hi R-users,
>
> I have a matrix similar to this. I would like to calculate the 
> number
> of 1 sequences in a row and also the length of the 1 sequence. For
> instance, in the example below, row number one has four sequences of
> number 1 (from left to right: 1; 1; 1,1; 1) and the corresponding
> SeqCount is 4 and SeqLenght 1,1,2,1.
>
> g <- c(0,0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1 ,1 ,0 ,1 ,1 ,1 ,0 
> ,1
> ,1 ,0 ,1 ,1 ,0 ,1 ,0 ,1 ,0 ,1 ,1 ,1 ,1 ,0 ,1 ,0 ,1 ,1 ,1 ,1 ,0 ,1 ,1
> ,1 ,1 ,0 ,1 ,1 ,0 ,1 ,0 ,0 ,1 ,0 ,0 ,0 ,1 ,0 ,1 ,0 ,0 ,1 ,1 ,0 ,1 ,1
> ,0 ,0 ,1 ,0 ,1 ,0 ,0 ,1 ,1 ,0 ,1 ,1 ,0 ,0 ,0 ,0 ,0 ,1 ,1 ,1 ,0 ,1 ,1
> ,0 ,0 ,1 ,0 ,0 ,1 ,1 ,0 ,1)
> dim(g) <- c(10,10)
>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
> [1,]    0    1    0    0    1    0    1    1    0     1
> [2,]    0    1    1    1    1    1    0    0    0     0
> [3,]    1    0    1    1    0    0    0    1    0     0
> [4,]    1    1    0    1    1    0    1    0    0     1
> [5,]    0    1    1    1    1    1    1    0    0     0
> [6,]    1    1    1    0    1    0    0    1    1     0
> [7,]    1    0    0    1    1    0    1    1    1     1
> [8,]    1    1    1    0    0    0    1    0    1     1
> [9,]    1    1    0    1    1    1    0    1    0     0
> [10,]    1    1    1    1    1    0    0    1    1     1
>
> The resulting datafmame should look like this:
> x <- "Rownumber SeqCount SeqLenght
> 1 4 1
> 1 4 1
> 1 4 2
> 1 4 1
> 2 1 5
> 3 3 1
> 3 3 2
> 3 3 1
> 4 4 2
> 4 4 2
> 4 4 1
> 4 4 1
> 5 1 6
> 6 3 3
> 6 3 1
> 6 3 2
> 7 3 1
> 7 3 2
> 7 3 4
> 8 3 3
> 8 3 1
> 8 3 2
> 9 3 2
> 9 3 3
> 9 3 1
> 10 2 5
> 10 2 3"
> x <- read.table(textConnection(x), header=TRUE)
> x
>
> Any idea how to do this in R?
>
> Best regards,
> Lauri
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 


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