On Thu, 2006-04-20 at 11:46 -0700, Sachin J wrote: > Hi, > > How can I accomplish this in R. Example: > > R1 R2 > 3 101 > 4 102 > 3 102 > 18 102 > 11 101 > > I want to find Sum(101) = 14 - i.e SUM(R1) where R2 = 101 > Sum(102) = 25 - SUM(R2) where R2 = 102 > > TIA > Sachin
Presuming that your data is in a data frame called DF: > DF R1 R2 1 3 101 2 4 102 3 3 102 4 18 102 5 11 101 At least three options: > with(DF, tapply(R1, R2, sum)) 101 102 14 25 > aggregate(DF$R1, list(R2 = DF$R2), sum) R2 x 1 101 14 2 102 25 > by(DF$R1, DF$R2, sum) INDICES: 101 [1] 14 ------------------------------------------------------ INDICES: 102 [1] 25 See ?by, ?aggregate and ?tapply and ?with. HTH, Marc Schwartz ______________________________________________ [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
