[R] how to find indices of particular array elements

ecoinfo ecoinformatics at gmail.com
Mon Oct 17 11:39:37 CEST 2005


How about the function which?

?which

On 10/17/05, Jonathan Williams
<jonathan.williams at pharmacology.oxford.ac.uk> wrote:
> Dear R helpers,
>
> I have a largish matrix (1300 x 1300) and I wish to find the row and column
> numbers that identify particular elements whose values I know in advance
> (for example, the row and column numbers for the maximum value of the
> matrix).
>
> I have looked in the help manual and found the functions 'row' and 'col' for
> finding the indices of a matrix. But, I can't figure out how to use them to
> obtain the indices of the matrix element with maximum value, despite over an
> hour of trying!
>
> Many thanks for your help,
>
> Jonathan Williams
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>


--
Xiaohua Dai, Dr.
--------------------------------------------------------------------------------
* Postdoctoral in elephant-tree ecosystem simulation
---------------------------------------------------------------------------------
Centre for Systems Research, Durban Institute of Technology
P.O.Box 953, Durban 4000, South Africa
Tel: +27-31-2042737(O) Fax: +27-31-2042736(O)
Mobile: +27-723682954




More information about the R-help mailing list