?tapply -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111
> -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Peng Cai > Sent: Thursday, December 03, 2009 11:50 AM > To: r-help@r-project.org > Subject: [R] Two-way/Three-way sum. > > Hi R Users, > > I'm wondering how can I calculate two (or three) way sum of a variable. > A > sample data is: > > State Month Year Value > NC Jan 1996 1 > NC Jan 1996 2 > NC Feb 1997 2 > NC Feb 1997 3 > NC Mar 1998 3 > NC Mar 1998 4 > NY Jan 1996 4 > NY Jan 1996 5 > NY Feb 1997 5 > NY Feb 1997 6 > NY Mar 1998 6 > NY Mar 1998 7 > > I'm trying to sum up "value" column by State*Month and by > State*Month*Year. > Also, I may need to calculate mean value along with "sum". > > Any help would be greatly appreciated, > > Thanks, > Peng > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting- > guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
