getting all pairwise combinations of elements in a character string
combn(letters[1:5], 2)
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [1,] "a" "a" "a" "a" "b" "b" "b" "c" "c" "d" [2,] "b" "c" "d" "e" "c" "d" "e" "d" "e" "e"
On Thu, Feb 12, 2009 at 12:20 PM, Levi Waldron
<lwaldron at uhnres.utoronto.ca> wrote:
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
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