[R] aggregate vs merge

[David Winsemius]

On Jun 14, 2010, at 10:06 PM, skan wrote:

>
> Hello
>
> Can someone explain me the difference between aggregate and merge,  
> please?
> I've read the help on both commands but I don't understant the  
> difference.
>

Merge adds data from one dataframe to another based on a matching  
process. Aggregate, which is a wrapper for tapply, works within one  
dataframe to apply a chosen function to "like" rows.

-- 
David.