Hi Adai, It works!! Thanks a lot!!
Hui-Yi On Fri, Sep 12, 2008 at 11:26 AM, Adaikalavan Ramasamy < [EMAIL PROTECTED]> wrote: > 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. >> > > [[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.