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...tion cummax() seems to have a bug. > x <- c(NA, 0) > storage.mode(x) <- "integer" > cummax(x) [1] NA 0 The correct result of this case should be NA NA. The mistake in [ https://github.com/wch/r-source/blob/trunk/src/main/cum.c#L130-L136] may be the reason. Best Regards, Dongcan -- Dongcan Jiang Team of Search Engine & Web Mining School of Electronic Engineering & Computer Science Peking University, Beijing, 100871, P.R.China [[alternative HTML version deleted]]

...elements in -i". > > > Suggesting that no bounds checking on -i takes place. > > > John > > Indeed! > Thanks a lot John, for the perspective and clarification! > > I'm committing a patch to the documentation now. Thank you both and also credits to Dongcan Jiang for pointing out to me that errors were indeed not generated in this case. I agree with the decision. It's interesting to notice that now the only way an error is generated is when index-vector subsetting is done using mixed positive and negative indices, e.g. x[c(-1,1)]. /Henrik >...

In Section 'Indexing by vectors' of 'R Language Definition' (http://cran.r-project.org/doc/manuals/r-release/R-lang.html#Indexing-by-vectors) it says: "Integer. All elements of i must have the same sign. If they are positive, the elements of x with those index numbers are selected. If i contains negative elements, all elements except those indicated are selected. If i is