Re: [R] Second largest element from each matrix row

From: Santosh Srinivas <santosh.srinivas_at_gmail.com>
Date: Tue, 26 Apr 2011 17:57:09 +0530

would this work (shorter)?

apply(a, 1, function(x) x[order(x)[2]])

On Tue, Apr 26, 2011 at 5:31 PM, Lars Bishop <lars52r_at_gmail.com> wrote:
> Hi,
>
> I need to extract the second largest element from each row of a
> matrix. Below is my solution, but I think there should be a more efficient
> way to accomplish the same, or not?
>
>
>  set.seed(1)
>  a <- matrix(rnorm(9), 3 ,3)
>  sec.large <- as.vector(apply(a, 1, order, decreasing=T)[2,])
>  ans <- sapply(1:length(sec.large), function(i) a[i, sec.large[i]])
>  ans
>
> Thanks in advance for your help,
> Lars.
>
>        [[alternative HTML version deleted]]
>
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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. Received on Tue 26 Apr 2011 - 12:30:55 GMT

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