Hello all, I use affycomp library, in order to test different Methods. I can produce *.csv file from *.CEL files: library(affy) library(affycomp) library(affydata) library(tools) data.raw <- ReadAffy(filenames="./R/ME_cel/Expt1_R1.CEL", ... "./R/ME_cel/Expt14_R1.CEL") # read process finished eset <- mas5(data.raw) x <- exprs(eset) write.table(data.frame(x,check.names=FALSE),file="H:/Profile/Eigene Da teien/Dip_bak/Pr_sprach/R/excel/ME_133_1.csv",sep=",",col.names=NA,quo te=FALSE) Now I concentrated on 2 questions: 1. How can I get "Statndard data.frame" without Pre processing? I can accomplish this data.frame with affycomp further tests. (description in: http://affycomp.biostat.jhsph.edu/#whatisthis) 2. as I above file (ME_133_1.csv) for read.spikein to use wants, gets I error message: spikein133.ngenes <- 0 f <- "H:/Profile/Eigene Dateien/Dip_bak/Pr_sprach/R/excel/ME_133_1.csv" s <- read.spikein(f,"hgu133a") Error in "[.data.frame"(s, , rownames(pData(pd))) : undefined columns selected How can I correct my errors? Thanks, Mohammad Esad-Djou