Sorry I'm still learning R so here my question. I have a subroutine that I have made. I want to be able to return two items from it. One is an object (the nls object) the other is matrix/data.frame. I would like to pass both of these to another subroutine and also be able to use it outside as normal. My OO programming is not very good so if you can explain the details that would be great. One more question, I have a very large matrix coming from a file that I want to be able to select certain columns from that matrix and do the subroutine on them, and I would like to be able to group the columns so that I can do the subroutine on them in a somewhat automatic way. Thank you for all you help in advance. PB Research Technician Mass Spectrometry [[alternative HTML version deleted]]