Trying to avoid a loop
On Tue, 23 Jan 2001, Michael Roberts wrote:
Wow. That was a quick reply. Thanks... but see below. Michael J. Roberts Resource Economics Division, PMT USDA-ERS 202-694-5557
Thomas Lumley <thomas at biostat.washington.edu> 01/23 5:51 PM >>>
On Tue, 23 Jan 2001, Michael Roberts wrote:
Hello:
Although I could write a loop to do the following, I would like
to avoid this as it would be expensive. Does anyone know if
there is an R function that would make this faster?
Given a 3 dimensional array, say Z with dimensions {n,l,k}, I
would
like to create a matrix Y with dimensions {n,l}, each element of
which
contains the position {k} with the largest element that dimension.
apply(z,c(1,2),max) This is close, but not exactly what I am looking for. I don't want the maximum value, but the position of the maximum value. Is there something like an "argmax" I could put in for max?
apply(z,1:2, function(x) which(x==max(x))) -thomas -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._