R is pretty smart about duplicating only when necessary. That is, arguments passed to a function are copy-on-write. Also, I think (someone more knowledgeable please correct if I'm wrong) it may be better to use the data frame, which is just a list internally, because if you only modify one column, only that column is duplicated, not the entire data frame. If you were to use a matrix, the entire matrix would require duplication.
-Matt On Mon, 2010-05-24 at 09:29 -0500, gschu...@scriptpro.com wrote: > I understand that everything passed to an R function is passed "by > value". This would seem to include data frames, which my current > application uses heavily, both for storing program inputs, and holding > intermediate and final results. In trying to get greater performance > out of my R code, I am wondering if there is any clean way to access > data frames without having them copied all the time. Or is my only > option to make them global, and write to them using <<- ? > > I have considered using matrices, but I like the self-documenting aspect > of data frame column names. Input/output to disk is not the issue here, > as that does not take long in my case. It's just the internal parameter > passing that I'm concerned about. > > (I've checked R-FAQ, R-lang and searched the R-help archives, but didn't > see any specific mentions of this.) > > Thanks. > > Grant Schultz > > ______________________________________________ > 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.
