Another approach is to use expand.grid to create a data.frame of all possible combinations of elements of its input vectors: rowSums(expand.grid(0:5, 0:5, 0:5))
Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of R. Michael > Weylandt > Sent: Saturday, October 29, 2011 7:46 AM > To: Suleyman K > Cc: r-help@r-project.org > Subject: Re: [R] R help with different combinations of vectors of different > sizes > > Just add another outer wrapper: > > outer(1:5, outer(1:5, 1:5, "+"), "+") > > If you are going to arbitrarily long tuples, it may be worthwhile to > put this in a wrapper like so: > > tupleSums <- function(vec, n){ > stopifnot(all.equal(n, as.integer(n))) > n <- as.integer(n) > if (n == 1L) return(vec) > ans <- outer(vec, vec, "+") > if (n == 2L) return(ans) > else{ > for (i in 3:n) ans <- outer(vec, ans, "+") > } > return(ans) > } > > Though this really could be made much more efficient if you want: > e.g., for the n = 4 case, it would be better to take outer( outer(vec, > vec, "+"), outer(vec, vec, "+"), "+"). > > Michael > > On Sat, Oct 29, 2011 at 9:08 AM, Suleyman K <s.ka...@gmail.com> wrote: > > Hi, > > > > I am trying to get different combinations of a vector of different size and > > find their sum. For example, if I have a vector (i,j) where i and j can be > > anything from 0 to 5, i get these combinations (0,0), (0,1), (1,0), (1,1), > > (2,0), ...... (5,5) and find sum of these as 0, 1, 1, 2, ..... , 10. I used > > outer functions to get this and it worked. What if I have a vector (i,j,k) > > where all i, j , and k can be anything from 0 to 5. I want to do the same > > thing here. Get all the combinations and sum them up. (0,0,0) (0,0,1), > > (0,1,0), (1,0,0), .... (5,5,5) How can I get these combinations and find > > their sums? Thank you very much in advance. > > > > Uka > > > > [[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. ______________________________________________ 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.
