>>>>> Martin Maechler writes: >>>>> "TTLAM" == Thaler, Thorn, LAUSANNE, Applied Mathematics >>>>> <thorn.tha...@rdls.nestle.com> >>>>> on Thu, 6 Jan 2011 15:37:01 +0100 writes:
TTLAM> Kurt Hornik writes >>> >> if (!all(sapply(args, is.ordered)) || >>> >> !all(sapply(level.list, identical, y = level.set))) { >>> >>> I think it would be better to use something like >>> >>> ll <- lapply(args, levels) >>> >>> !all(sapply(ll, identical, ll[[1L]])) >>> >>> [using union() is not quite right] TTLAM> Yes definitely. This line is in fact just a relic from a previous idea I TTLAM> had. > I have now committed the amended proposal (rev 53925); > thank you for the feedbacks.. >>> The general comment is that if we support this I don't see why we >>> should >>> not also support c.ordered (and in fact also c.factor) with the same >>> restrictions (identical level sequences for ordered and level sets for >>> factors). We already have Ops.factor and Ops.ordered using the same >>> principle afaic. > Yes, I think, too. >>> If we add c.ordered, we should be able to encapsulate the identity of >>> levels testing into this, and simply use >>> >>> x <- c(...) >>> >>> and then call .Generic on the codes of x etc. TTLAM> Sounds reasonable. Ack. > Yes, adding c.factor() and c.ordered() seems reasonable in > principle. > However, S and R now have a more than 20 year old history of > silently coercing factors to there integer codes with c(), > that I'm not yet sure we can do this without breaking too much > code [[and I am pretty sure this topic has been discusses before]]. Yes, of course. But then we just made another backwards incompatible change, and R> c(ordered(1 : 3), ordered(4 : 6)) [1] 1 2 3 1 2 3 seems more like a bug to me :-) > I think we should start discussing the issue in a new thread > with proper Subject explicitly mention "c()" or > "c.factor"/"c.ordered". Yes! Best -k > Martin TTLAM> BR Thorn TTLAM> ______________________________________________ TTLAM> R-devel@r-project.org mailing list TTLAM> https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel