Hi all, I have a matrix like following > test=matrix(c(1:15),nrow=3,ncol=5) > colnames(test)=c("A","A","B","B","B") > test A A B B B [1,] 1 4 7 10 13 [2,] 2 5 8 11 14 [3,] 3 6 9 12 15 I want to calculate the average of each replicates, ie. I want the output to be A B [1,] 2.5 10 [2,] 3.5 11 [3,] 4.5 12 I can do this by looping through each level of the column name, but I was wondering if there is a function for calculating the average of replicates in one step. Thank you in advance. Wendy [[alternative HTML version deleted]]

Hi Wendy, On 3/27/2011 6:47 PM, Wendy Qiao wrote: > Hi all, > > > > I have a matrix like following > > > >> test=matrix(c(1:15),nrow=3,ncol=5) > >> colnames(test)=c("A","A","B","B","B") > >> test > > A A B B B > > [1,] 1 4 7 10 13 > > [2,] 2 5 8 11 14 > > [3,] 3 6 9 12 15 > > > > I want to calculate the average of each replicates, ie. I want the output to > be > > A B > > [1,] 2.5 10 > > [2,] 3.5 11 > > [3,] 4.5 12 > > > > I can do this by looping through each level of the column name, but I was > wondering if there is a function for calculating the average of replicates > in one step. This question has nothing to do with Bioconductor, so you should be asking on R-help. However, ?aggregate. Best, Jim > > > > Thank you in advance. > > Wendy > > > > > [[alternative HTML version deleted]] > > _______________________________________________ > Bioconductor mailing list > Bioconductor at r-project.org > https://stat.ethz.ch/mailman/listinfo/bioconductor > Search the archives: http://news.gmane.org/gmane.science.biology.informatics.conductor -- James W. MacDonald, M.S. Biostatistician Douglas Lab University of Michigan Department of Human Genetics 5912 Buhl 1241 E. Catherine St. Ann Arbor MI 48109-5618 734-615-7826 ********************************************************** Electronic Mail is not secure, may not be read every day, and should not be used for urgent or sensitive issues