[R] finding unique and max value from a data.frame

[jim holtman]

?aggregate

  x1 x2
1  a  4
2  b  3
3  c  2
4  a  1
5  c  2
6  f  3
7  g  4
8  f  5
> aggregate(x$x2, list(x$x1), max)
  Group.1 x
1       a 4
2       b 3
3       c 2
4       f 5
5       g 4
>


On Thu, Oct 23, 2008 at 8:30 PM, Srinivas Iyyer
<srini_iyyer_bio at yahoo.com> wrote:
> Hi group,
>
> How can I identify an element with max value among duplicated elements all in a data frame
>
> Example:
>
>> x1
>  x1 x2
> 1  a  4
> 2  b  3
> 3  c  2
> 4  a  1
> 5  c  2
> 6  f  3
> 7  g  4
> 8  f  5
>
>
> I want to be able to get a data frame with all unique(x1) with max value
>
>  x1 x2
> 1  a  4
> 2  b  3
> 3  c  2
> 5  c  2
> 7  g  4
> 8  f  5
>
>
> Could I get some help please.
> thanks
> srini
>
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-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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