It'd be doubly helpful if you could post desired output as well. If you haven't seen it before, the easiest way to post R data is to use the dput() function to get a plain-text (mailing list friendly) representation. If your data is large, dput(head(DATA, 30)) should suffice.
(We wouldn't want to clog those internet tubes...) Michael On Sat, Mar 3, 2012 at 8:55 PM, jim holtman <jholt...@gmail.com> wrote: > If you would post a subset of your data so that we can see what you > are talking about, we could probably help you come up with a solution. > > On Sat, Mar 3, 2012 at 7:50 PM, Mikhail Titov <m...@gmx.us> wrote: >> Hello! >> >> I’m having stacked data in a data.frame with 2 factors, ordered POSIXct, and >> actual value as numeric (as if for lattice::xyplot). >> >> I would like to calculate first difference using “diff” function within >> corresponding subsets/partitions. Since data.frame is organized by factors >> and has sorted dates, it seems like "by" is a good candidate for the job. >> However it returns just a dumb list of vectors. >> >> It seems that I can use either expand.grid to remap results of "by" and hope >> that I won't mess up order, or I can use >> "unique(subset(x,select=c(foo,bar)))" >> >> In overall it looks like quite many steps for such task not counting >> assignment of those differences back to original data.frame starting from >> 2nd position in each partition (as diff returns shorter vector). >> >> Am I on the right track or is there an easier way to do that? >> >> Mikhail >> >> ______________________________________________ >> 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. > > > > -- > Jim Holtman > Data Munger Guru > > What is the problem that you are trying to solve? > Tell me what you want to do, not how you want to do it. > > ______________________________________________ > 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.
