aa[order(aa)] is the same as sort, although sort is much quicker and has lower memory requirements:
> aa <- rnorm(10000000) > all(aa[order(aa)] == sort(aa)) [1] TRUE > system.time(sort(aa)) user system elapsed 7.27 0.08 8.25 > system.time(aa[order(aa)]) user system elapsed 29.58 0.32 31.31 (yes, I have a pitifully slow computer) HTH, Andrew. On Mar 29, 8:01 am, Tal Galili <tal.gal...@gmail.com> wrote: > Yes Johannes - That helped, thank you. > > On Sat, Mar 28, 2009 at 11:50 PM, Johannes Huesing > <johan...@huesing.name>wrote: > > > > > Tal Galili <tal.gal...@gmail.com> [Sat, Mar 28, 2009 at 06:48:36PM CET]: > > > Hello people. > > > > I wish to reorder a simple vector of numbers by another vector of the > > order > > > (and then do the same, but with a data frame rows) > > > > I try this (which doesn't work) : > > > > aa <- c(3, 1 ,2 ) > > > > aa[aa] > > > [1] 2 3 1 > > > To my mind, it does what you told it to, and therefore "works" > > in my book. The routine orders the numbers by placing the third element > > first, the first second, and the second third. > > > Maybe aa[order(aa)] does what you mean it to do? > > > Best wishes > > > Johannes > > > -- > > Johannes Hüsing There is something fascinating about science. > > One gets such wholesale returns of conjecture > > mailto:johan...@huesing.name from such a trifling investment of fact. > >http://derwisch.wikidot.com (Mark Twain, "Life on the > > Mississippi") > > -- > ---------------------------------------------- > > My contact information: > Tal Galili > Phone number: 972-50-3373767 > FaceBook: Tal Galili > My > Blogs:http://www.r-statistics.com/http://www.talgalili.comhttp://www.biostatistics.co.il > > [[alternative HTML version deleted]] > > ______________________________________________ > r-h...@r-project.org mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guidehttp://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.
