By "an argument named 'use.names' is included for concatenation", I meant something like this, that someone might try.
> c(as.Date("2016-01-01"), use.names=FALSE) use.names "2016-01-01" "1970-01-01" See, 'use.names' is in the output. That's precisely because 'c.Date' doesn't have 'use.names', so that 'use.names' is absorbed into '...'. -------------------------------------------- On Sun, 25/9/16, Martin Maechler <maech...@stat.math.ethz.ch> wrote: Subject: Re: [Rd] Undocumented 'use.names' argument to c() Cc: "R-devel" <R-devel@r-project.org> Date: Sunday, 25 September, 2016, 10:14 PM >>>>> Suharto Anggono Suharto Anggono via R-devel <r-devel@r-project.org> >>>>> on Sun, 25 Sep 2016 14:12:10 +0000 writes: >> From comments in >> http://stackoverflow.com/questions/24815572/why-does-function-c-accept-an-undocumented-argument/24815653 >> : The code of c() and unlist() was formerly shared but >> has been (long time passing) separated. From July 30, >> 1998, is where do_c got split into do_c and do_unlist. > With the implementation of 'c.Date' in R devel r71350, an > argument named 'use.names' is included for > concatenation. So, it doesn't follow the documented > 'c'. But, 'c.Date' is not explicitly documented in > Dates.Rd, that has 'c.Date' as an alias. I do not see any c.Date in R-devel with a 'use.names'; its a base function, hence not hidden .. As mentioned before, 'use.names' is used in unlist() in quite a few places, and such an argument also exists for lengths() and all.equal.list() and now c() ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel