Why is strptime always returning a vector of length 9 ?
Thanks. It seems that the source of my confusion comes from using first using str() (and then once on the wrong track, it is easier to miss the information a man page that also describes POSIXct that is itself a vector of length equal to the number of entries it contains). With the current example:
str(xd)
POSIXlt[1:9], format: "2007-03-09" "2007-05-31" "2008-11-12" "2008-11-12" ... A quick inspection of the output does indicate a something with nine elements, but the elements appear to be "2007-03-09", "2007-05-31", etc... possibly creating confusion. To make it even more confusing I have:
x[1]
[1] "March 09, 2007"
str(x[1])
chr "March 09, 2007" For what it is worth, I think that the behavior of the extract operator "[" (defined as a S3 method "[.POSIXlt()") is inconsistent with the output of length() (default method for lists). L.
On Sun, 2009-08-09 at 11:45 -0500, Jeff Ryan wrote:
The reason is in the ?strptime under value:
'strptime' turns character representations into an object of class
'"POSIXlt"'. The timezone is used to set the 'isdst' component
and to set the '"tzone"' attribute if 'tz != ""'.
And POSIXlt is a list of length 9.
HTH
Jeff
On Sun, Aug 9, 2009 at 10:35 AM, Gabor
Grothendieck<ggrothendieck at gmail.com> wrote:
Try this to see its components:
str(unclass(xd))
List of 9 $ sec : num [1:6] 0 0 0 0 0 0 $ min : int [1:6] 0 0 0 0 0 0 $ hour : int [1:6] 0 0 0 0 0 0 $ mday : int [1:6] 9 31 12 12 30 30 $ mon : int [1:6] 2 4 10 10 6 6 $ year : int [1:6] 107 107 108 108 109 109 $ wday : int [1:6] 5 4 3 3 4 4 $ yday : int [1:6] 67 150 316 316 210 210 $ isdst: int [1:6] 0 1 0 0 1 1 and read R News 4/1 for more. On Sun, Aug 9, 2009 at 10:20 AM, laurent<lgautier at gmail.com> wrote:
Dear List,
I am having an issue with strptime (see below).
I can reproduce it on R-2.8, R-2.9, and R-2.10-dev, I tempted to see
either a bug or my misunderstanding (and then I just don't currently see
where).
# setup:
x <- c("March 09, 2007", "May 31, 2007", "November 12, 2008", "November
12, 2008", "July 30, 2009", "July 30, 2009" )
# showing the problem
length(x)
6
xd <- strptime(x, format = "%B %d, %Y") length(xd)
9
xd[1:9]
[1] "2007-03-09" "2007-05-31" "2008-11-12" "2008-11-12" "2009-07-30" [6] "2009-07-30" NA NA NA
length(strptime(rep(x, 2), format="%B %d, %Y"))
[1] 9
strptime(rep(x, 2), format="%B %d, %Y")[1:12]
[1] "2007-03-09" "2007-05-31" "2008-11-12" "2008-11-12" "2009-07-30" [6] "2009-07-30" "2007-03-09" "2007-05-31" "2008-11-12" "2008-11-12" [11] "2009-07-30" "2009-07-30 Any pointer would be appreciated. L.
______________________________________________ R-devel at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
______________________________________________ R-devel at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel