Or to expand just a hair on Joshua's suggestion, is the following what you want:
> x <- 1:10 > names(x) <- letters[1:10] > x a b c d e f g h i j 1 2 3 4 5 6 7 8 9 10 > df <- data.frame(x=x,y=LETTERS[1:10],row.names=names(x)) > df x y a 1 A b 2 B c 3 C d 4 D e 5 E f 6 F g 7 G h 8 H i 9 I j 10 J > y <- t(df[,1,drop=FALSE])[1,] > y a b c d e f g h i j 1 2 3 4 5 6 7 8 9 10 > identical(x,y) [1] TRUE Cheers, Bert On Sat, Aug 18, 2012 at 8:16 AM, Joshua Ulrich <josh.m.ulr...@gmail.com> wrote: > I don't know if this is better, but it's the most obvious/shortest I > could come up with. Transpose the data.frame column to a 'row' vector > and drop the dimensions. > > R> identical(nv, drop(t(df))) > [1] TRUE > > Best, > -- > Joshua Ulrich | about.me/joshuaulrich > FOSS Trading | www.fosstrading.com > > > On Sat, Aug 18, 2012 at 10:03 AM, Martin Maechler > <maech...@stat.math.ethz.ch> wrote: >> Today, I was looking for an elegant (and efficient) way >> to get a named (atomic) vector by selecting one column of a data frame. >> Of course, the vector names must be the rownames of the data frame. >> >> Ok, here is the quiz, I know one quite "cute"/"slick" answer, but was >> wondering if there are obvious better ones, and >> also if this should not become more idiomatic (hence "R-devel"): >> >> Consider this toy example, where the dataframe already has only >> one column : >> >>> nv <- c(a=1, d=17, e=101); nv >> a d e >> 1 17 101 >> >>> df <- as.data.frame(cbind(VAR = nv)); df >> VAR >> a 1 >> d 17 >> e 101 >> >> Now how, can I get 'nv' back from 'df' ? I.e., how to get >> >>> identical(nv, .......) >> [1] TRUE >> >> where ...... only uses 'df' (and no non-standard R packages)? >> >> As said, I know a simple solution (*), but I'm sure it is not >> obvious to most R users and probably not even to the majority of >> R-devel readers... OTOH, people like Bill Dunlap will not take >> long to provide it or a better one. >> >> (*) In my solution, the above '.......' consists of 17 letters. >> I'll post it later today (CEST time) ... or confirm >> that someone else has done so. >> >> Martin >> >> ______________________________________________ >> R-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel