... or perhaps using rep() to do the indexing directly instead of matching:
dfrm[ ave(dfrm$v1, dfrm$v1, FUN = function(x)rep(c(TRUE,FALSE),c(3,length(x)-3))), ] There's probably another 6 dozen ways to do it, especially if you access packages like data.table, plyr, etc. Cheers, Bert Bert Gunter "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." -- Clifford Stoll On Wed, Dec 2, 2015 at 12:26 PM, David Winsemius <dwinsem...@comcast.net> wrote: > >> On Dec 2, 2015, at 10:09 AM, Ragia Ibrahim <ragi...@hotmail.com> wrote: >> >> Dear Group, >> I have a data frame that such as >> >> v1 v2 v3 v4 >> 1 1 3 6 >> 1 1 5 6 >> 1 1 8 0 >> 1 2 6 1 >> 1 2 4 0 >> 1 3 4 4 >> 1 3 5 4 >> 1 3 6 3 >> 1 3 7 1 >> >> 2 4 3 7 >> 2 5 5 4 >> 2 5 8 2 >> 2 1 6 1 >> 2 1 4 0 >> 2 1 4 3 >> 2 1 5 2 >> 3 1 6 1 >> 3 6 7 0 >> >> 3 6 3 6 >> 3 6 5 6 >> 3 6 8 0 >> 3 6 6 1 >> 3 2 4 0 >> 3 2 4 4 >> 3 2 5 4 >> 3 2 6 3 >> 3 2 7 1 >> 3 5 9 5 >> 3 6 9 5 >> >> >> the result required is each first 3 rows, from distinct v2 column for each >> v1 column >> >> >> v1 v2 v3 v4 >> 1 1 3 6 >> 1 2 6 1 >> 1 3 4 4 >> 2 4 3 7 >> 2 5 5 4 >> 2 1 6 1 >> 3 6 3 6 >> 3 2 4 0 >> 3 5 9 5 > > > Probably something along the lines of > > dfrm[ ave(dfrm$v1, dfrm$v1, FUN=seq_along) %in% 1:3 , ] > > >> >> >> thanks in advance >> [[alternative HTML version deleted]] > > Future postings should be in plain text. > > — > > 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. ______________________________________________ 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.
