Hi, I think the Rle functions should preserve semantics from stats. Here is at least one case where they do not: > median(Rle(NA),na.rm=TRUE) Error in x[FALSE] : subscript out of bounds # but: > median(c(NA),na.rm=TRUE) [1] NA # some other border cases: > median(c()) NULL # arguably correct, if you read the docs and appreciate that as(NA,class(c())) is NULL > median(Rle()) Error in x[FALSE] : subscript out of bounds # should probably be NULL Agreed? Can be fixed? Thanks! ~ Malcolm Cook Computational Biology / Shilatifard Lab - Stowers Institute for Medical Research - Kansas City