Dear ????, 15 is very big number for me (perhaps for R as well :() so I have tried following:
mat <- expand.grid(rep(list(c("1", "X", "2")),4)); mat[mat[,3]=="2",] -- View this message in context: http://r.789695.n4.nabble.com/Combinations-tp2955065p2955338.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.