In my previous post the format should have been "%m %d". Terry Mu <muster <at> gmail.com> writes:
: : thank you, : : one more question: : : How can I list only values for given condition? : for example, I want to see only data from febuary, i.e. month=2? : : On Sun, 5 Dec 2004 16:26:11 +0000 (UTC), Gabor Grothendieck : <ggrothendieck <at> myway.com> wrote: : > Terry Mu <muster <at> gmail.com> writes: : > : > : : > : a data set like this: : > : > : > : : > : year month day count : > : 2001 1 1 10 : > : 2001 1 2 11 : > : .... : > : 2004 7 17 8 : > : .... : > : : > : basically it is a count of of some numbers everyday through a few years : > : : > : now I'd like to get the mean of the count for every day. : > : : > : I thought I can do this using for and ifelse, : > : but is there a simple way to do this? I wish a function like : > : mean(count, 'only when year, month, day are equal') could do this. : > : > You want to represent your dates as objects of the Date class : > and then use tapply. (See ?as.Date, ?Date, ?tapply, ?paste, ?with. : > Also look up ?aggregate and ?by and read about dates in R News 4/1.) : > Assuming DF is your data frame: : > : > Dates <- with(DF, : > as.Date( paste(year, month, day, sep="-") ) : > ) : > tapply(DF$count, Dates, mean) : > : > : > : > ______________________________________________ : > R-help <at> stat.math.ethz.ch mailing list : > https://stat.ethz.ch/mailman/listinfo/r-help : > PLEASE do read the posting guide! http://www.R-project.org/posting- guide.html : > : : ______________________________________________ : R-help <at> stat.math.ethz.ch mailing list : https://stat.ethz.ch/mailman/listinfo/r-help : PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html : : ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
