Petr, Jorge, Daniel, Yes you could also use outer() instead of expand.grid(). This is quite useful to know.
Also I didn't know you could turn a matrix into a vector by setting its dimensions to NULL like that. I always used as.vector( m ). And (as I've just discovered) you can use it to reconfigure the matrix's shape to any that contains the same number of elements. Thanks very much one and all. Regards Desmond -----Original Message----- From: Petr PIKAL [mailto:petr.pi...@precheza.cz] Sent: 29 August 2011 07:24 To: Campbell, Desmond Cc: r-help@R-project.org Subject: Odp: [R] all combinations of the elements of two vectors Hi > > Dear R-help readers, > > I'm sure this problem has been answered but I can't find the solution. > > I have two vectors > v1 <- c("a","b") > v2 <- c(1,2,3) > I want an easy way to produce every possible combination of v1, v2 elements > Ie I want to produce > c("a1","a2","a3", "b1","b2","b3") Another option is z<-outer(x,y, paste, sep="") dim(z)<-NULL > z [1] "a1" "b1" "c1" "a2" "b2" "c2" "a3" "b3" "c3" which gives the result in different order or z<-as.vector(t(z)) > z [1] "a1" "a2" "a3" "b1" "b2" "b3" "c1" "c2" "c3" Which gives you desired order. Regards Petr > > regards > Desmond > > Desmond Campbell > Dept of Biostatistics and Computing, Institute of Psychiatry (KCL), > PO Box 20, De Crespigny Park, Denmark Hill London, SE5 8AF > > Tel 020 7848 0309 > Email d.campb...@iop.kcl.ac.uk<mailto:d.campb...@iop.kcl.ac.uk> > > > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.
