On 16 December 2016 at 10:19, Martin Maechler wrote: | >>>>> Jennifer Lyon <jennifer.s.l...@gmail.com> | >>>>> on Thu, 15 Dec 2016 09:33:30 -0700 writes: | | > On the documentation page for DateTimeClasses, in the Examples section, | > there are the following two lines: | > | > format(.leap.seconds) # the leap seconds in your time zone | > print(.leap.seconds, tz = "PST8PDT") # and in Seattle's | > | > The second line (using print) seems to ignore the tz argument, and prints | > the dates in my time zone, while: | > | > format(.leap.seconds, tz = "PST8PDT") | > | > does print the dates in PST. The code in | > https://github.com/wch/r-source/blob/trunk/src/library/base/R/datetime.R | > around line 234 looks like the ... argument is passed to print, not to | > format. | > | > print.POSIXct <- | > print.POSIXlt <- function(x, ...) | > { | > max.print <- getOption("max.print", 9999L) | > if(max.print < length(x)) { | > print(format(x[seq_len(max.print)], usetz = TRUE), ...) | > cat(' [ reached getOption("max.print") -- omitted', | > length(x) - max.print, 'entries ]\n') | > } else print(if(length(x)) format(x, usetz = TRUE) | > else paste(class(x)[1L], "of length 0"), ...) | > invisible(x) | > } | > | > The documentation for print() on this page seems to be silent on tz as an | > argument, but I do believe the example using print() does not work as | > advertised. | | > Thanks. | > | > Jen | | Thank you, Jen! | Indeed, both your observation and your diagnosis are correct: | This has been a misleading example and needs amending (or the | code is changed, see below). | | The most simple fix would be to replace 'print(' by | 'format('; then the example would work as advertized. | That change has two drawbacks still: | | 1) format(.) examples on the help of print.POSIXct() where | format.POSIXct() is *not* documented | | 2) It *would* make sense that print.POSIXct() allowed for a 'tz' argument | (and maybe 'usetz' too). This/these would be (an) extra | argument(s) rather than passing '...' not just to print() but | also to format()rathere | | My personal preference would tend to add both | tz = "" | and usetz = TRUE | to the formal arguments of print.POSIXct and pass them to the | format(.) calls.
I think that is a good idea. I have been by this a few times too. Dirk -- http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
