Your code below changes the class of the time index from "Date" to "character". Perhaps you want "yearmon" class. The following averages all values in each month producing a series with time class "yearmon". See ?yearmon
library(zoo) z <- zoo(c(0.1423065, -0.03276228, -0.0652789, -0.04999873, -0.01447902, 0.22265729), as.Date(c(11047, 11075, 11108, 11138, 11169, 11200))) z aggregate(z, as.yearmon, mean) # Its also possible, though normally undesirable, to use "character" as your # index class but then for it to make sense you will need to choose a # representation which sorts appropriately under the usual rules for sorting: aggregate(z, format(time(z), "%Y-%m"), mean) On Mon, Mar 3, 2008 at 2:13 AM, Megh Dal <[EMAIL PROTECTED]> wrote: > Suppose I have following dataset : > > head(data1) > Date Return > 1 03/31/00 0.14230650 > 2 04/28/00 -0.03276228 > 3 05/31/00 -0.06527890 > 4 06/30/00 -0.04999873 > 5 07/31/00 -0.01447902 > 6 08/31/00 0.22265729 > > Now I convert it to zoo object : > > > data11 = zoo(data1[,2], as.Date(data1[,1], format="%m/%d/%y")) > > head(data11) > 2000-03-31 2000-04-28 2000-05-31 2000-06-30 2000-07-31 2000-08-31 > 0.14230650 -0.03276228 -0.06527890 -0.04999873 -0.01447902 0.22265729 > > Clearly those are monthly data. Therefore I want to convert it to mm-yy > format. I used following code : > data111 = zoo(coredata(data11), format(index(data11), "%m/%y")) > > However what I got is that : > > head(data111) > 01/01 01/02 01/03 01/04 01/05 01/06 > -0.001388889 -0.016274826 -0.047707664 0.001104362 -0.077961541 0.017637141 > > tail(data111) > 12/02 12/03 12/04 12/05 12/06 12/07 > 0.058660676 -0.018067833 -0.055569851 0.007142888 0.051162052 0.052643733 > > It is evident that month order has been changed. Can anyone here tell me how > to get correct order like : > > 01/01, 02/01, 03/01.................. > > Your help is highly appreciated > > Regards, > > > --------------------------------- > > [[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.
