Very nice, Phil. Thank you. -----Original Message----- From: Phil Spector [mailto:spec...@stat.berkeley.edu] Sent: Monday, September 20, 2010 1:28 PM To: Doran, Harold Cc: R-help Subject: Re: [R] Sorting and subsetting
Harold - Two ways that come to mind: 1) do.call(rbind,lapply(split(tmp,tmp$index),function(x)x[1:5,])) 2) subset(tmp,unlist(tapply(foo,index,seq))<=5) - Phil Spector Statistical Computing Facility Department of Statistics UC Berkeley spec...@stat.berkeley.edu On Mon, 20 Sep 2010, Doran, Harold wrote: > Suppose I have a data frame, such as the one below: > > tmp <- data.frame(index = gl(2,20), foo = rnorm(40)) > > And further assume it is sorted by index and then by the variable foo. > > tmp <- tmp[order(tmp$index, tmp$foo) , ] > > Now, I want to grab the first N rows of tmp for each index. In the end, what > I want is the data frame 'result' > > tmp1 <- subset(tmp, index == 1) > tmp2 <- subset(tmp, index == 2) > > tmp1 <- tmp1[1:5,] > tmp2 <- tmp2[1:5,] > result <- rbind(tmp1, tmp2) > > Does anyone see a way to subset and subsequently bind without a loop? > > Harold > > > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > ______________________________________________ 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.