Thanks again! On Thu, Dec 3, 2009 at 2:19 PM, David Winsemius <dwinsem...@comcast.net>wrote:
> > On Dec 3, 2009, at 2:14 PM, Peng Cai wrote: > > Also, can I control for number of decimal places printed. Like when I use > "mean" function. By default it shows upto 7 dec. Thanks! > > > > print(4.567891234, digits=3) > [1] 4.57 > > > > > 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 >>> >>> >> > > 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.
