Here is a third solution. A[B$DayOfYear, "x"] <- A[B$DayOfYear, "x"] - B$x
Its assumes B's days are a subset of A's but if that's not the case then you would need to intersect them first: ?intersect On Sat, Jul 26, 2008 at 5:26 PM, <[EMAIL PROTECTED]> wrote: > I have two vectos (list) that represent a years of data. Each "row" is > represented by the day of year and the quantity that was sold for that day. I > would like to form a new vector that is the difference between the two years > of data. A sample of A (and similarly B) looks like: > >> A[1:5,] > DayOfYear x > 1 1 1429 > 2 2 3952 > 3 3 3049 > 4 4 2844 > 5 5 2219 >> > > D <- A - B > > This works just fine if A and B are both the same length. How is the best way > to handle the situation where A and B are of different lengths? If the day of > year exists in both vectors (lists) then I just want the coorespondng "row" > in D to be the difference btween A and B values. If the "row" doesn't exist > in either A or B then the difference should be treated as if the missing > "row" was zero. Is this feasible? > > Thank you. > > Kevin > > ______________________________________________ > 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.
