help(rowttests) says that fac needs to be a factor. So how about ?
m <- matrix( rnorm(30), nc=6 ) genotype <- c("a", "a", "b", "b", "c", "c") w1 <- which( genotype %in% c("a", "b") ) w2 <- which( genotype %in% c("a", "c") ) w3 <- which( genotype %in% c("b", "c") ) list( ab = rowttests( m[ , w1], factor( genotype[w1] ) ), ac = rowttests( m[ , w2], factor( genotype[w2] ) ), bc = rowttests( m[ , w3], factor( genotype[w3] ) ) ) Regards, Adai Hui-Yi Chu wrote:
Dear R list, I think my question maybe easy for you but I really spent entire day to resolve it. Say I have a matrix, rows are 6000 genes, columns(1-6) are 3 genotypes (a,b,c) with 2 repeat. I have to use two groups each time for t-test, a vs. c or b vs. c, but I dont know how to write correct codes. Below is my codes, the last two lines are needed to be corrected.... library("genefilter") ef <- exprs(esetsub) kk <- factor(esetsub$genotype == c("a", "c")) tt <- rowttests(ef[,c(1,2,5,6)], kk) ps. column 1-6 is a,a,b,b,c,c depending on the document, the kk should be a factor.. Any suggestions are really appreciated!! Best regards, Hui-Yi [[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.