I have a data frame. Let\'s call him bob:
> head(bob)
phenotype exclusion
GSM399350 3- 4- 8- 25- 44+
Update: Here's an example of something that doesn't work. I thought it would, but I think that the stringsAsFactors option only works on character strings - it leaves the factors alone.
Try this:
bob2 <- data.frame(bob, stringsAsFactors = FALSE)
Generally speaking, whenever you're having problems with factors that should be characters, there's a stringsAsFactors setting somewhere to help you (including a global setting).