Federico, Why not 1> convert to data frame dfo <- as.data.frame(mat) 2> take unique items with ?unique df<- unique(dfo) 3> add an index to the unique itmes df$unique <- 1:nrow(df) 4> merge the two data.frames combi <- merge(dfo,df) 5> extract the index? combi$unique
Kees On Thursday 26 October 2006 18:47, Federico Calboli wrote: > Hi All, > > I have two numerical matrices of 2 columns and many rows. > > The two coulumns of matrix (1) form a number of 'pairs' of numbers, e.g: > > [,1] [,2] > [1,] 1 0 > [2,] 3 4 > [3,] 3 4 > [4,] 5 8 > [5,] 1 0 > [6,] 1 0 > [7,] 6 7 > > Matrix (2) contains the *unique* pairs: > > [,1] [,2] > [1,] 1 0 > [2,] 3 4 > [3,] 5 8 > [4,] 6 7 > > > I would like to create a vector matching the pairs in matrix (1) to the > unique pairs in matrix (2), e.g: > > [1] 1 2 2 3 1 1 4 > > (done by hand) > > match() does not seem to be able to handle pairs, and I don't seem to be > able to find an elegant solution... > > Cheers, > > Federico ______________________________________________ R-help@stat.math.ethz.ch 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.