On Apr 5, 2014, at 9:51 AM, Kate Ignatius wrote: > I'm trying to work out the average of a certain value by chromosome. > I've done the following, but it doesn't seem to work: > > Say, I want to find average AD for chromosome 1 only and paste the > value next to all the positions on chromosome 1: > > [sam$chrom == '1'] <- > (sam$ad)/(colSums(sam[c(1:nrow(sam$chrom=='1'))],))
It "looks" wrong to me because of the mismatching lengths of the lhs and rhs but since you have not provided a test dataset that's all I will say. The usual way to calculate a function within categorical groupings that will be "re-inserted" alongside the original dataframe is to use `ave`: sam$mmad <- with( sam, ave(ad, chrom, FUN=mean) ) > > I know this is convoluted and possible wrong... but I would like to do > this for all chromosomes. > > Thanks! -- David Winsemius Alameda, CA, USA ______________________________________________ R-help@r-project.org mailing list 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.
