You could use the data.table package require(data.table) DT <- data.table(Friend1 = sample(LETTERS, 10, replace = TRUE), Friend2 = sample(LETTERS, 10, replace = TRUE), Indicator = 1) ALL <- data.table(unique(expand.grid(DT))) setkey(ALL) OTHERS <- ALL[!DT] OTHERS[, Indicator := 0]
RESULT <- rbind(DT, ALL) Best Simon On 01 Nov 2013, at 10:32, Thomas <thomas.ches...@nottingham.ac.uk> wrote: > I have data that looks like this: > > Friend1, Friend2 > A, B > A, C > B, A > C, D > > And I'd like to generate some more rows and another column. In the new column > I'd like to add a 1 beside all the existing rows. That bit's easy enough. > > Then I'd like to add rows for all the possible directed combinations of rows > not included in the existing data. So for the above I think that would be: > > A, D > D, A > B, C > C, B > B, D > C, A > D, B > D, C > > and then put a 0 in the column beside these. > > Can anyone suggest how to do this? > > I'm using R version 2.15.3. > > Thank you, > > Thomas Chesney > This message and any attachment are intended solely for the addressee and may > contain confidential information. If you have received this message in error, > please send it back to me, and immediately delete it. Please do not use, > copy or disclose the information contained in this message or in any > attachment. Any views or opinions expressed by the author of this email do > not necessarily reflect the views of the University of Nottingham. > > This message has been checked for viruses but the contents of an attachment > may still contain software viruses which could damage your computer system, > you are advised to perform your own checks. Email communications with the > University of Nottingham may be monitored as permitted by UK legislation. > > ______________________________________________ > 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.
