Dear Srini,
Here is one way:
# Data set
x=read.table(textConnection("fruit weight
1 apple 1.3
2 apple 1.5
3 apple 1.6
4 orange 1.4
5 orange 1.6"),header=TRUE)
x[tapply(x$weight,x$fruit,which.max),]
apple orange
1.6 1.6
or
Try also
x[cumsum(tapply(x$weight,x$fruit,which.max)),]
fruit weight
3 apple 1.6
5 orange 1.6
HTH,
Jorge
On Sun, Sep 7, 2008 at 10:24 PM, Srinivas Iyyer
<[EMAIL PROTECTED]>wrote:
> dear group,
> i have a data matrix with some replicate items with different values. I
> want to extract the row with max value.
>
> for example:
> > x
> fruit weight
> 1 apple 1.3
> 2 apple 1.5
> 3 apple 1.6
> 4 orange 1.4
> 5 orange 1.6
>
>
> x is a data frame.
> I want to extract unique items from fruits that has max weight.
>
> that is:
>
> 3 apple 1.6
> 5 orange 1.6
>
> I want to be able to use apply functions. Could some one lend some help
> please.
>
> Thanks
> srini
>
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