Sorry! -- Change that to drop = FALSE ! drop(t(df[,1,drop=FALSE])) t(df[,1,drop=FALSE])[1,]
-- Bert On Sat, Aug 18, 2012 at 9:37 AM, Bert Gunter <bgun...@gene.com> wrote: > Yes, but either > > drop(t(df[,1,drop=TRUE])) > > or > > t(df[,1,drop=TRUE])[1,] > > does work. My minimal effort to check timings found that the first > version was a hair faster. > > -- Bert > > On Sat, Aug 18, 2012 at 9:01 AM, Rui Barradas <ruipbarra...@sapo.pt> wrote: >> Hello, >> >> A bit more general >> >> nv <- c(a=1, d=17, e=101); nv >> nv2 <- c(a="a", d="d", e="e") >> df2 <- data.frame(VAR = nv, CHAR = nv2); df2 >> >> identical( nv, drop(t( df2[1] )) ) # TRUE >> identical( nv, drop(t( df2[[1]] )) ) # FALSE >> >> Rui Barradas >> >> Em 18-08-2012 16:16, Joshua Ulrich escreveu: >>> >>> 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 >> >> >> ______________________________________________ >> 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 -- 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
