Slight edit? --------
It is rumored that on Wed, 26 Jan 2005 09:24:44 -0500 "Liaw, Andy" <[EMAIL PROTECTED]> wrote: > See if this does what you want: > > > m <- matrix(round(runif(24)), 4, 6) # simulate some data > > m > [,1] [,2] [,3] [,4] [,5] [,6] > [1,] 0 1 0 1 0 1 > [2,] 0 1 1 1 0 0 > [3,] 1 1 1 0 0 0 > [4,] 1 0 0 0 1 0 > > library(gtools) # Install the gregmisc package if you don't have > > it. idx <- combinations(nrow(m), 2) > > res <- m[idx[,1],] + m[idx[,2]] I think you missed a "," (if you want pairwise row sums) res <- m[idx[,1],] + m[idx[,2],] > > rownames(res) <- paste(idx[,1], idx[,2], sep="+") > > res > [,1] [,2] [,3] [,4] [,5] [,6] > 1+2 0 1 0 1 0 1 > 1+3 1 2 1 2 1 2 > 1+4 1 2 1 2 1 2 > 2+3 1 2 2 2 1 1 > 2+4 1 2 2 2 1 1 > 3+4 2 2 2 1 1 1 > > Andy > > > > From: Jacques VESLOT > > > > It is part of a function to determine Dice's index in the > > framewok of AFLP > > analysis. > > > > X is a binary matrix which value for each strain (lines) and > > each base pair > > (columns) is 1 where there is a peak and 0 where there is no peak as > > biologists explained to me. > > > > The first step is to compare each strain with one another by > > counting the > > number of 0, 1 and 2, respectively where there is no peak, > > one peak or 2 > > peaks for each base pair. > > > > In that respect, I want to add together each pair of X's lines. > > > > For the moment, there is a double loop calculating, at each > > step, the sum of > > two lines as a vector Y and counting the number of 0, 1 and 2 > > in it for > > inclusion in other operations. > > > > I read your posting... > > > > Thanks for helping, > > > > Jacques VESLOT > > > > > > -----Message d'origine----- > > De : Adaikalavan Ramasamy [mailto:[EMAIL PROTECTED] > > Envoyé : mercredi 26 janvier 2005 15:57 > > À : [EMAIL PROTECTED] > > Cc : R-help > > Objet : Re: [R] Still avoiding loops > > > > > > Please give a simple example of the input data and output that you > > desire. It is difficult to understand from you partial codes what > > you mean. For example what is Y ? > > > > Are you trying to find add values from pairs of rows ? If so, > > please see > > my posting "pairwise difference operator" where I wanted to find the > > differences between pairs of columns. > > http://tolstoy.newcastle.edu.au/R/help/04/07/1633.html > > > > Otherwise, please send a sample input and output. Thank you. > > > > Regards, Adai > > > > > > On Wed, 2005-01-26 at 11:40 +0400, Jacques VESLOT wrote: > > > Dear all, > > > > > > I have a matrix X with 47 lines and say 500 columns - > > values are in {0,1}. > > > I'd like to compare lines. > > > > > > For that, I first did: > > > > > > for (i in 1:(dim(X)[1]-1)) > > > for (j in (i+1):dim(X)[1]) { > > > Y <- X[i,]+Y[j,] > > > etc. > > > > > > but, since it takes a long time, I would prefer avoding loops; > > > for that, my first idea was to add this matrix: > > > > > > X1=X[,rep(1:46,46:1)] > > > > > > to this one: > > > > > > res=NULL > > > for (i in (2:47)) res=c(res,i:47) > > > > > > X2=X[,res] > > > > > > (Is it a nice alternative way ?) > > > Is there a way to create the second matrix X2 without a > > loop, such as for > > X1 > > > ? > > > > > > Thanks in advance, > > > > > > Jacques VESLOT > > > > > > ______________________________________________ > > > R-help@stat.math.ethz.ch mailing list > > > https://stat.ethz.ch/mailman/listinfo/r-help > > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > > > > > > > ______________________________________________ > > R-help@stat.math.ethz.ch mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > > > > > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > -------- -- [EMAIL PROTECTED] "There are ten church members by inheritance for every one by conviction." [Anonymous] t ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
