Simon Urbanek wrote: > Wacek, > > Peter gave you a full answer explaining it very well. If you really > want to be able to trace each instance yourself, you have to learn far > more about R internals than you apparently know (and Peter hinted at > that). Internally x=1 an x=c(1) are slightly different in that the > former has NAMED(x) = 2 whereas the latter has NAMED(x) = 0 which is > what causes the difference in behavior as Peter explained. The reason > is that c(1) creates a copy of the 1 (which is a constant [=unmutable] > thus requiring a copy) and the new copy has no other references and > thus can be modified and hence NAMED(x) = 0.
simon, thanks for the explanation, it's now as clear as i might expect. now i'm concerned with what you say: that to understand something visible to the user one needs to "learn far more about R internals than one apparently knows". your response suggests that to use r without confusion one needs to know the internals, and this would be a really bad thing to say.. i have long been concerned with that r unnecessarily exposes users to its internals, and here's one more example of how the interface fails to hide the guts. (and peter did not give me a full answer, but a vague hint.) vQ ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
