[R] Merge partially duplicated rows

[David Winsemius]

On Aug 3, 2009, at 9:24 AM, Rnewbie wrote:

>
> Dear all,
>
> I have a dataset, and I wanted to merge the rows with duplicated IDs  
> by
> calculating the means or medians from the duplicate rows. I tried  
> using the
> command duplicated(x), but it only tells where the duplicated rows  
> are.

You might want to look at the ave function. It will calculate a  
function within IDs and you can assign that as another row in the  
datafrme before you exclude the duplicates.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT