# [R] Finding Coordinate of Max/Min Value in a Data Frame

DavidM.UK david.merritt at bris.ac.uk
Wed Jun 11 14:09:48 CEST 2008

```Firstly surely (CL,PC5) = -0.7416656 is the minima?

I think something like this should work, though I'm not sure

library(MASS)
data(crabs)
crab.pca <- prcomp(crabs[,4:8],retx=TRUE)
x<- crab.pca\$rotation
c.len = length(x[,1])
r.len = length(x[1,])
maxy = which(x == min(x))
x.co <- ceiling(maxy/c.len)
y.co <- maxy-(x.co-1)*c.len

Though I'm sure their is a more simple solution to your problem,

Best,

David
U Bristol

Edward Wijaya-2 wrote:
>
> Hi,
>
> Suppose I have the following data frame.
>
> __BEGIN__
>
>> library(MASS)
>> data(crabs)
>> crab.pca <- prcomp(crabs[,4:8],retx=TRUE)
>> crab.pca\$rotation
>          PC1        PC2        PC3        PC4        PC5
> FL 0.2889810  0.3232500 -0.5071698  0.7342907  0.1248816
> RW 0.1972824  0.8647159  0.4141356 -0.1483092 -0.1408623
> CL 0.5993986 -0.1982263 -0.1753299 -0.1435941 -0.7416656
> CW 0.6616550 -0.2879790  0.4913755  0.1256282  0.4712202
> BD 0.2837317  0.1598447 -0.5468821 -0.6343657  0.4386868
>
> __END__
>
> Is there a way to identify the "coordinate" of a max/min value of all the
> points above.
>
> For example the coord of maximum value is (RW,PC2) = 0.865,
> and coord of min value is (CW,PC2) = - 0.288.
>
> --
> Gundala Viswanath
>
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