Also, can I control for number of decimal places printed. Like when I use "mean" function. By default it shows upto 7 dec. Thanks!
On Thu, Dec 3, 2009 at 2:08 PM, Peng Cai <pengcaimaill...@gmail.com> wrote: > Thanks David for your suggestions. > > > On Thu, Dec 3, 2009 at 2:03 PM, David Winsemius <dwinsem...@comcast.net>wrote: > >> >> On Dec 3, 2009, at 1:50 PM, Peng Cai wrote: >> >> 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. >>> >> >> ?tapply >> >> as in >> >> sum.tbl <- with(dftbl, tapply(Value, list(State, Month), sum) ) >> >> >> Also, I may need to calculate mean value along with "sum". >>> >> >> Use the mean function in the above formulation to get means, length to get >> counts, or perhaps summary .... or one of the several packages that offer a >> "describe" function. So many functions, so little time. >> >> -- David >> >> >> >>> 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<http://www.r-project.org/posting-guide.html> >>> and provide commented, minimal, self-contained, reproducible code. >>> >> >> David Winsemius, MD >> Heritage Laboratories >> West Hartford, CT >> >> > [[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.
