>>>>> "WK" == Wacek Kusnierczyk <waclaw.marcin.kusnierc...@idi.ntnu.no> >>>>> on Mon, 23 Feb 2009 12:06:32 +0100 writes:
Thank you, Wacek, though .. "wrong mailing list" WK> the man page for relational operators (see, e.g., ?'<') says: WK> " WK> Binary operators which allow the comparison of values in atomic vectors. WK> Arguments: WK> x, y: atomic vectors, symbols, calls, or other objects for which WK> methods have been written. WK> " WK> it is somewhat surprizing that the following works: WK> '<'(1) WK> # logical(0) WK> '<'() WK> # logical(0) WK> '<'(1,2,3) WK> # TRUE a bit surprising (sic!), indeed, even for me. Thanks for your notice and report! If you'd looked a bit in the sources, you'd seen that they really are supposed to be binary only. A very small change in the sources does accomplish this, passes the standard checks (and I cannot imagine reasonable code that would have relied on the more lenient behavior), so this will have changed in one of the next versions of R-devel. Martin Maechler, ETH Zurich WK> what does 'binary' mean here, precisely? in the first two examples, one WK> might suspect that '<' treats the missing arguments as missing values, WK> but this would not be coherent with what the man page says: WK> " WK> Missing values ('NA') and 'NaN' values are regarded as WK> non-comparable even to themselves, so comparisons involving them WK> will always result in 'NA'. WK> " WK> i can't find the above explained in the documentation. typing `<` shows WK> that it is a WK> function(e1, e2) .Primitive("<") WK> how come can/should it work with no complaint on input that does not WK> consist of exactly 2 arguments? WK> in scheme (which is claimed to have been an inspiration for r), < works WK> on an arbitrary number of arguments: WK> (<) WK> ;; #t WK> (< 1) WK> ;; #t WK> (< 1 2 3) WK> ;; #t WK> (< 1 2 0) WK> ;; #f WK> but there < is an arity-dispatched procedure, not a binary one, and it WK> produces sensible output for any number of arguments (arguably for n=0, 1). WK> vQ ______________________________________________ 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.