> > d[match(unique(d$fac),d$fac),] The following does the same thing a little more directly (and quickly) d[ !duplicated(d$fac), ]
Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf > Of Gang Chen > Sent: Friday, December 13, 2013 1:35 PM > To: arun > Cc: R help > Subject: Re: [R] dataframe manipulation > > Perfect! Thanks a lot, A.K! > > > On Fri, Dec 13, 2013 at 4:21 PM, arun <smartpink...@yahoo.com> wrote: > > > > > > > Hi, > > Try: > > d[match(unique(d$fac),d$fac),] > > A.K. > > > > > > On Friday, December 13, 2013 4:17 PM, Gang Chen <gangch...@gmail.com> > > wrote: > > Suppose I have a dataframe defined as > > > > L3 <- LETTERS[1:3] > > (d <- data.frame(cbind(x = 1, y = 1:10), fac = sample(L3, 10, replace > > = TRUE))) > > > > x y fac > > 1 1 1 C > > 2 1 2 A > > 3 1 3 B > > 4 1 4 C > > 5 1 5 B > > 6 1 6 B > > 7 1 7 A > > 8 1 8 A > > 9 1 9 B > > 10 1 10 A > > > > I want to extract those rows that are the first occurrences for each level > > of factor 'fac', which are basically the first three rows above. How can I > > achieve that? The real dataframe is more complicated than the example > > above, and I can't simply list all the levels of factor 'fac' by > > exhaustibly listing all the levels like the following > > > > d[d$fac=='A' | d$fac=='B' | d$fac=='C', ] > > > > Thanks, > > Gang > > > > [[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. > > > > > > [[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.
