Re: [R] Data Manipulations - Group By equivalent

From: Frank E Harrell Jr <>
Date: Sun 02 Jul 2006 - 10:43:45 EST

zubin wrote:
> Hello, a beginner R user - boy i wish there was a book on just data
> manipulations for SAS users learning R (equivalent to the SAS DATA
> STEP).. Okay, my question:
> I have a panel data set, hotel data occupancy by month for 12 months,
> 1000 hotels. I have a field labeled 'year' and want to consolidate the
> monthly records using an average into 1000 occupancy numbers - just a
> simple average of the 12 months by hotel. In SQL this operation is
> pretty easy, a group by query (group by hotel where year = 2005, avg
> occupancy) - how is this done in R? (in R language not SQL). Thx!
> -zubin
> ______________________________________________
> mailing list
> PLEASE do read the posting guide!

This is in the most basic R documentation. Please read it.

Frank E Harrell Jr   Professor and Chair           School of Medicine
                      Department of Biostatistics   Vanderbilt University

______________________________________________ mailing list
PLEASE do read the posting guide!
Received on Sun Jul 02 10:44:30 2006

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.1.8, at Sun 02 Jul 2006 - 14:14:26 EST.

Mailing list information is available at Please read the posting guide before posting to the list.