But it's simpler and probably faster to use R's built-in capabilities.
?which ## note the arr.ind argument!)
As an example:
test <- matrix(rnorm(24), nr = 4)
which(test==max(test), arr.ind=TRUE)
row col
[1,] 2 6
So this gives the row and column indices of the max, from which row and
column names can easily be obtained from the dimnames attribute of the
matrix.
Note: This assumes that the object in question is a matrix, NOT a data
frame, for which it would be slightly more complicated.
-- Bert
On Tue, Oct 11, 2011 at 3:06 PM, Carlos Ortega <c...@qualityexcellence.es>wrote:
> Hi,
>
> With this code you can find row and col names for the largest value applied
> to your example:
>
> r.m.tmp<-apply(dat,1,max)
> r.max<-names(r.m.tmp)[r.m.tmp==max(r.m.tmp)]
>
> c.m.tmp<-apply(dat,2,max)
> c.max<-names(c.m.tmp)[c.m.tmp==max(c.m.tmp)]
>
> It's inmediate how to get the same for the smallest and build a function to
> calculate everything and return a list.
>
>
> Regards,
> Carlos Ortega
> www.qualityexcellence.es
>
> 2011/10/11 Ben qant <ccqu...@gmail.com>
>
> > Hello,
> >
> > I'm looking to get the values, row names and column names of the largest
> > and
> > smallest values in a matrix.
> >
> > Example (except is does not include the names):
> >
> > > x <- swiss$Education[1:25]
> > > dat = matrix(x,5,5)
> > > colnames(dat) = c('a','b','c','d','c')
> > > rownames(dat) = c('z','y','x','w','v')
> > > dat
> > a b c d c
> > z 12 7 6 2 10
> > y 9 7 12 8 3
> > x 5 8 7 28 12
> > w 7 7 12 20 6
> > v 15 13 5 9 1
> >
> > > #top 10
> > > sort(dat,partial=n-9:n)[(n-9):n]
> > [1] 9 10 12 12 12 12 13 15 20 28
> > > # bottom 10
> > > sort(dat,partial=1:10)[1:10]
> > [1] 1 2 3 5 5 6 6 7 7 7
> >
> > ...except I need the rownames and colnames to go along for the ride with
> > the
> > values...because of this, I am guessing the return value will need to be
> a
> > list since all of the values have different row and col names (which is
> > fine).
> >
> > Regards,
> >
> > Ben
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > 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.
> >
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> 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.
>
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