Hello, Following should work.
m <- matrix(round(runif(16,0,2)),nrow=2) colnames(m) <- c("A","A","B","B","C","C","D","D") m2 <- m #matrix(, nrow=dim(m)[1], ncol=dim(m)[2]/2) z <- 1 ss <- seq(1,dim(m)[2],2) for(j in ss){ for(i in 1:dim(m)[1]){ m2[i,j] <- substring(m[i,ss[z]] == m[i,ss[z]+1],1,1) } z <- z + 1 } m2 <- m2[,ss] colnames(m2) <- colnames(m)[ss] When your data set is large, then you should try to code this using apply. Best, Matthias > > Hi, > > I have an R programming problem and I havent found anything > in the documentation yet: > > I have a data matrix, in which two neighbouring columns > represent replicates of the same experiment, e.g. something like this: > > A A B B C C > row1 1 1 1 2 2 2 > row2 1 1 1 1 1 2 > > I would like to test, if the values for the two replicates in > a row are the same or if they differ and generate a new > matrix with the results of the tests, something like this: > > A B C > row1 T F T > row2 T T F > > Any hint will be appreciated! > > Georg > > ______________________________________________ > 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