martin.becker at mx.uni-saarland.de
2006-Dec-29 10:53 UTC
[Rd] bug in cut.Date() (PR#9433)
Full_Name: Martin Becker
Version: 2.4.1
OS: WinXP/Linux
Submission from: (NULL) (134.96.96.42)
When using cut.Date() with 'breaks="year"', the month of the
breakpoints is
properly set to January, but the day of month is not set to 1.
This leads to a strange behaviour, see the following example:
>
cut(as.Date(c("2000-01-17","2001-01-13","2001-01-20")),breaks="y")
[1] 2000-01-17 2000-01-17 2001-01-17
Levels: 2000-01-17 2001-01-17
I asked on R-devel (2006-12-20), if there are reasons for this (in my opinion
strange) behaviour, but since I got no answer, I suppose this behaviour is not
intended and thus there is a bug in cut.Date().
The corresponding code fragment which defines the first breakpoint in
the case 'breaks="year"' reads (2.4.1, 2.4.1 patched, 2.5.0):
if (valid == 4) {
start$mon <- 0
incr <- 366
}
I think, the code fragment above should better read:
if (valid == 4) {
start$mon <- 0
start$mday <- 1
incr <- 366
}
The following patch to src/library/base/R/dates.R should do this change:
301c301
< if(valid == 4) { start$mon <- 0; incr <- 366 }
---> if(valid == 4) { start$mon <- 0; start$mday <- 1; incr <-
366 }
Kind regards,
Martin