R help - Dec 2009 - extract value from first column based on value in second column

Hi all,

I have two columns of data, the first consists of parameter estimates and
the second probability estimates.  I would like to extract the value from
the first column based on the max value of column two, but not sure how to
do this other than by extracting the value and then manually finding the
value in the first column.  Anyone know how to do this?  Basically, I need
to find the row number for the maximum in column two and use that value to
extract the value at the same row number in column one.

Thanks for any help,

Wade

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Will something like this work for you:
> x <- cbind(runif(10), runif(10))
> x
            [,1]      [,2]
 [1,] 0.26550866 0.2059746
 [2,] 0.37212390 0.1765568
 [3,] 0.57285336 0.6870228
 [4,] 0.90820779 0.3841037
 [5,] 0.20168193 0.7698414
 [6,] 0.89838968 0.4976992
 [7,] 0.94467527 0.7176185
 [8,] 0.66079779 0.9919061
 [9,] 0.62911404 0.3800352
[10,] 0.06178627 0.7774452
> x[which.max(x[,2]),1]
[1] 0.6607978
>

On Tue, Dec 29, 2009 at 1:48 PM, Wade Wall <wade.wall@gmail.com> wrote:
> Hi all,
>
> I have two columns of data, the first consists of parameter estimates and
> the second probability estimates.  I would like to extract the value from
> the first column based on the max value of column two, but not sure how to
> do this other than by extracting the value and then manually finding the
> value in the first column.  Anyone know how to do this?  Basically, I need
> to find the row number for the maximum in column two and use that value to
> extract the value at the same row number in column one.
>
> Thanks for any help,
>
> Wade
>
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>
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> PLEASE do read the posting guide
>
http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

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