How about m <- outer(mystring, mystring, paste, sep="") m[upper.tri(m)]
Kellie Wills -----Original Message----- From: r-help-boun...@r-project.org on behalf of Levi Waldron Sent: Thu 2/12/2009 12:20 PM To: r-help@r-project.org Subject: [R] getting all pairwise combinations of elements in a characterstring I'm able to do this as follows, but am wondering if anyone knows a simpler way which still avoids explicit loops? > (mystring <- letters[1:5]) [1] "a" "b" "c" "d" "e" > unlist(sapply(mystring[-length(mystring)], + function(x) paste(x,mystring[(grep(x,mystring)+1):length(mystring)],sep=""))) a1 a2 a3 a4 b1 b2 b3 c1 c2 d "ab" "ac" "ad" "ae" "bc" "bd" "be" "cd" "ce" "de" > -- Levi Waldron post-doctoral fellow Jurisica Lab, Ontario Cancer Institute Division of Signaling Biology IBM Life Sciences Discovery Centre TMDT 9-304D 101 College Street Toronto, Ontario M5G 1L7 ______________________________________________ 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.