> On Nov 21, 2015, at 4:44 AM, Axel Urbiz <axel.ur...@gmail.com> wrote: > > Hello, > > I would like to sort the df below, such that it sorts y1 in decreasing order > for tt == 1 and in increasing order for > tt == 0. My solution is below, but curious if there might be something better > (meaning faster in this case). > > Actually, if instead if implicitly sorting, I could add a variable ‘rank’ as > in my ‘hope’ data frame below, that would work too (as I just need the > ranking of observations, not necessarily the data explicitly sorted in the > results). > > ### Sample data > y1 <- c(50,100,200,20,400,100,500,1000,12,25) > tt <- factor(c(1,1,1,0,0,0,0,1,0,0)) > df <- data.frame(y1, tt) > > ### My solution > library(dplyr) > sorted <- rbind(df[df$tt == 1, ] %>% arrange(desc(y1)), > df[df$tt == 0, ] %>% arrange(y1)) > > ### What I hope to get > hope <- data.frame(df, > rank = c(4, 3, 2, 6, 9, 8, 10, 1, 5, 7)) > hope[order(hope$rank),]
Couldn’t this just be accomplished with a bit of Boolean arithmetic: df[ with(df,order( c(1,-1)[ 1+(tt==1) ]*y1 ) ), ] This inverts the y1-ordering of (tt==1) cases. If you need that third column, then cbind the “rank" vector with seq(nrow(df)) but I would avoid using the name “rank" for obvious reasons. (And note that `df` is also an R function name.) > > > Thanks for any help. > > Best Axel. > [[alternative HTML version deleted]] Please. This is a plain-text list. > > ______________________________________________ > R-help@r-project.org 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. David Winsemius Alameda, CA, USA ______________________________________________ R-help@r-project.org 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.
