Hi R-people

I have a question concerning subsetting. I have a dataframe which contains among other variables the variable "subject". For each subject number there are several rows, e.g.:
subject  treatment concentration day
19          a          15,4       1
19          a          18,3       2
19          a           2,3       3

etc.

Im trying to subset the dataframe to get for example only the rows of subject 19 and subject 15. I tried this with

        nameofdataframe[nameofdataframe$subject==c(19,15),]

This doesnt work as i get less rows than i should and a warning as well. How can i succeed doing this?

Thanks a lot

Gabi


