[R] Second largest element from each matrix row

From: Lars Bishop <lars52r_at_gmail.com>
Date: Tue, 26 Apr 2011 08:01:46 -0400


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.

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