Fantastic! Thanks very much! Where can I read more about the double assignment statement at the bottom? Closest I could get was a double for loop, which takes a long time....
Bill.Venables wrote: > > Here is a suggestion > >> con <- textConnection("AnimalA,AnimalB,Score > A1,A2,1 > A1,A3,2 > A1,A4,3 > A2,A3,4 > A2,A4,5 > A3,A4,6 > ") >> tst <- read.csv(con) >> close(con) >> an <- with(tst, sort(unique(c(as.character(AnimalA), > as.character(AnimalB))))) >> M <- array(0, c(length(an), length(an)), list(an, an)) >> i <- match(tst$AnimalA, an) >> j <- match(tst$AnimalB, an) >> M[cbind(i,j)] <- M[cbind(j,i)] <- tst$Score >> >> M > A1 A2 A3 A4 > A1 0 1 2 3 > A2 1 0 4 5 > A3 2 4 0 6 > A4 3 5 6 0 >> > > > Bill Venables > CSIRO Laboratories > PO Box 120, Cleveland, 4163 > AUSTRALIA > Office Phone (email preferred): +61 7 3826 7251 > Fax (if absolutely necessary): +61 7 3826 7304 > Mobile: +61 4 8819 4402 > Home Phone: +61 7 3286 7700 > mailto:[EMAIL PROTECTED] > http://www.cmis.csiro.au/bill.venables/ > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of knussear > Sent: Saturday, 10 May 2008 10:18 AM > To: r-help@r-project.org > Subject: [R] Create pairwise table from columns? > > > Hi Group > > I have a large data set of individual pairwise values (250,000 rows) > that I > need to reshape into a pairwise matrix for mantel tests of these values > versus genetic distances. > > the data are currently in columns formatted like so > AnimalA, AnimalB, Score > A1, A2, S1 > A1, A3, S2 > A1, A4, S3 > A2, A3, S4 > A2, A4, S5 > A3, A4, S6 > ...,....,.... > > > I need the final matrix to be formatted as > A1 A2 A3 A4 > A1 0 S1 S2 S3 > A2 S1 0 S4 S5 > A3 S2 S4 0 S6 > A4 S3 S4 S6 0 > > are there any functions/packages that will make this easier? > > Thanks > > Ken > -- > View this message in context: > http://www.nabble.com/Create-pairwise-table-from-columns--tp17158538p171 > 58538.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > > -- View this message in context: http://www.nabble.com/Create-pairwise-table-from-columns--tp17158538p17162698.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.