Is the following what you want? > a <- c(1,2,3,4,4,4,5,5) > b <- c(11,7,4,9,8,3,12,4) > split(b, a) $1 [1] 11
$2 [1] 7 $3 [1] 4 $4 [1] 9 8 3 $5 [1] 12 4 Note that your df<-cbind(a,b) produces a matrix, not the data.frame that your df suggests you want. Use df<-data.frame(a,b) to make a data.frame. Then you could do with(df, split(a,b)) to operate on the a and b in the data.frame df. 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 Marco Guerzoni > Sent: Tuesday, March 13, 2012 10:51 AM > To: r-help@r-project.org > Subject: [R] reshaping a dataset for a network > > dear all, > apologizes for bothering with a probably stupid question but I really > don' t know how to proceed. > > I have a dataset which look like df > > a <- c(1,2,3,4,4,4,5,5) > b <- c(11,7,4,9,8,3,12,4) > df <-cbind(a,b) > > I would like to have one which looks like this: > > a > 1 11 > 2 7 > 3 4 > 4 9 8 3 > 5 12 4 > > a are vertex of a network, b the edges. In the data the lenght of a is > about 50000 > > I read several posts about reshape, reshape2, split, ldply but I > couldn't manage to do it. The problem seems to be that the is not a real > panel. > > Any help would be really appreciated, > my best regards > Marco > > ______________________________________________ > 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.
