> gene2 <- c(1.35,1.55,1.00)
> gene3 <- c(-1.10,-1.50,-1.25)
> gene4 <- c(-1.20,-1.30,-1.00)
> gene1 <- c(1.00,1.50,1.25)
> rowcolnames <- list(c("gene1","gene2","gene3","gene4"),
+ c("Eric","Peter","Anna"))
> gendat <- matrix(c(gene1,gene2,gene3,gene4), nrow=4, ncol=3,
+ byrow=TRUE, dimnames = rowcolnames)
> gendat
Eric Peter Anna
gene1 1.00 1.50 1.25
gene2 1.35 1.55 1.00

> apply(gendat,1,mean)
gene1 gene2 gene3 gene4
1.250000 1.300000 -1.283333 -1.166667
> apply(gendat,2,mean)
Eric Peter Anna
0.0125 0.0625 0.0000
> meanexprsval <- apply(gendat,1,mean)
> o <- order(meanexprsval,decreasing=TRUE)
> o
[1] 2 1 4 3


> gendat[order(meanexprsval,decreasing=TRUE),]
> gendat[c(1,2),]
> gendat[c("gene1","gene2"),]

> meanexprsval > 0
gene1 gene2 gene3 gene4
TRUE TRUE FALSE FALSE




Eric Peter Anna
gene2 1.35 1.55 1.00
gene1 1.00 1.50 1.25
gene4 -1.20 -1.30 -1.00
gene3 -1.10 -1.50 -1.25