Look at methods(as.data.frame) Define your specialized columns to have a newly defined class, say "myclass". Then write as.data.frame.myclass It will be similar to the function you already have in the lapply statement. Now your statement X <- X[ok,] should work.
Rich On Sat, Oct 19, 2019 at 8:20 PM Rolf Turner <[email protected]> wrote: > > > I am writing a function that involves a data frame "X" some columns of > which have attributes. I replace X by a data frame with a subset of the > rows of X: > > X <- X[ok,] > > where "ok" is a logical vector. When I do this the attributes of the > columns (which I need to retain) are lost (except for the "class" and > "levels" attributes of columns which are factors). > > Is there any sexy way to retain the attributes of the columns? > > So far the only approach that I can work out is to extract the > attributes prior to subsetting and put them back after subsetting. > > Like unto: > > SaveAt <- lapply(X,attributes) > X <- X[ok,] > lX <- lapply(names(X),function(nm,x,Sat){ > attributes(x[[nm]]) <- Sat[[nm]] > x[[nm]]},x=X,Sat=SaveAt) > names(lX) <- names(X) > X <- as.data.frame(lX) > > This seems to work, but is rather kludgy. Is there a better way? > > Thanks for any pointers. > > cheers, > > Rolf Turner > > -- > Honorary Research Fellow > Department of Statistics > University of Auckland > Phone: +64-9-373-7599 ext. 88276 > > ______________________________________________ > [email protected] mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see 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.
