[R] Trying to avoid a loop

Michael Roberts mroberts at ers.usda.gov
Tue Jan 23 23:57:20 CET 2001


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?

Thanks a lot
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