Dear Group, table(Rle) seems to ignore empty levels. x = Rle(c(2,3,1,2,3,2),rep(2,6)) levels(x) = as.character(0:5) table(x) table(factor(as.numeric(x),levels=as.character(0:5))) I am using R 2.15.1 and IRanges 1.17.1. Regards, Pete ____________________ Peter M. Haverty, Ph.D. Genentech, Inc. phaverty at gene.com