HI Santosh, The simplest way I can think of is (after you import the data) to do: tapply(Zvo$V2, YEAR, sum)
The question is how to get "YEAR". You could do that if you know how to play with date objects. Another option is to do something like: YEAR <- as.data.frame(strsplit(Zvo$V2, "-"))[1,] For example: as.data.frame(strsplit(c( "1995-04-01" , "1995-04-02"), "-"))[1,] I am sure others can think of better ways. Tal ----------------Contact Details:------------------------------------------------------- Contact me: tal.gal...@gmail.com | 972-52-7275845 Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) | www.r-statistics.com (English) ---------------------------------------------------------------------------------------------- On Wed, Mar 17, 2010 at 8:20 AM, <santosh.ar...@csiro.au> wrote: > > Hello there > > I have a DAILY data set (as shown below) with Date and > Streamflow from April 1995 to Aug 2006. I want a yearly sum > the streamflow value (for each year - first and last > incomplete year). > > Does anyone know how to do this in R? > > I have tried everything I could think of, e.g. imported the > streamflow data as time series using: > > flowdata <- ts(ZVo[,2],start = c(1995,4,1), frequency = 7) # > perhaps frequency = 365 is the better one and tried to > aggregate using aggregate() without success > > >ZVo > V1 V2 > 1 1995-04-01 0.002766309 > 2 1995-04-02 0.002402973 > 3 1995-04-03 0.002254335 > 4 1995-04-04 0.002221305 > 5 1995-04-05 0.002180017 > 6 1995-04-06 0.002031379 > 7 1995-04-07 0.001957060 > 8 1995-04-08 0.001940545 > 9 1995-04-09 0.001924030 > 10 1995-04-10 0.001783650 > . > . > . > 4156 2006-08-16 0.02861272 > 4157 2006-08-17 0.03652353 > 4158 2006-08-18 0.05372419 > 4159 2006-08-19 0.05630058 > 4160 2006-08-20 0.06274154 > 4161 2006-08-21 0.06981833 > > Many thanks > > Santosh > > ______________________________________________ > 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. > [[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.
