Hello.
Im trying to post the following message in R-Help. I think I must send it via email to do so, so here it is: Hello, I need help with some code. Basically, I have experiments results which I need to process. I have 2 dataframes with 3 columns Df1 <- data.frame (Date, Cellline, Data) Df2 <- data.frame (Date, Cellline, Control) I want for the entire column Df1-Data to be subtracted by the corresponding Df2-Controls which Columns Date and Cellline coincide through some type of loop. So the structure is: Df1$Data <- Df1$Data - Df2$Control [when (Df1$Celline == Df2$Celline & Df1$Date == Df2$Date]) Each Control has several dozen Data values which are linked through Data and Celline. Of course, the data.frames are of different dimensions. I've tried several approaches and failed miserably. Any suggestions? Thank you in advance for any. Thanks. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.