similar to: weird "max" behavior for difftime class

I have just become painfully aware that objects of class "difftime", generated by the difference of two POSIXct objects, carry a "units" attribute, which flashes by when the object is printed, for example. The pain was occasioned when I tried to turn these objects into numberic objects for use elsewhere as a covariate. as.numeric(difftime object) simply turns off the units

Since both comparison and negation are well-defined for time differences, I wonder why abs and division are not defined for class difftime. This behavior is clearly documented on the man page: "limited arithmetic is available on 'difftime' objects"; but why? Both are natural, semantically sound, and useful operations and I see no obvious reason that they should give an error:

Since both comparison and negation are well-defined for time differences, I wonder why abs and division are not defined for class difftime. This behavior is clearly documented on the man page: "limited arithmetic is available on 'difftime' objects"; but why? Both are natural, semantically sound, and useful operations and I see no obvious reason that they should give an error:

Full_Name: Barry Rowlingson Version: 1.6.0 OS: RH8 i386 Submission from: (NULL) (148.88.136.205) Strange things happen if I premultiply a difftime() object with a number. Example: > d1 <- difftime(Sys.time(),Sys.time()) > d2 <- 1 * difftime(Sys.time(),Sys.time()) > d3 <- difftime(Sys.time(),Sys.time()) * 1 > d1 Time difference of 0 secs - thats fine > d2 [1] 0

Is there a way to specify the color of the main title, the subtitle, or the axis labels? I mean, for instance, something like title(main="cougar", col=2) For me, the above command produces the color black; that is, the "col" argument has no effect. I'm on a Windows 2000 machine with > version _ platform i386-pc-mingw32 arch i386 os mingw32 system

I am trying to do ephemeris calculations in R, which involves calculating an elapsed time. As illustrated below, difftime seems to have problems with my method, since the fractional day is sometimes the correct 0.5 and sometimes the incorrect 0.46. I am doing this on with R-2.6.1 on a powerpc-apple-darwin8.10.1 system. I get the same results for as.POSIXlt() instead of as.POSIXct(), but the

Dear all, I have a vector generated using the function strptime: > my.dt [1] "2004-04-19 08:35:00 W. Europe Daylight Time" "2004-04-19 09:35:00 W. Europe Daylight Time" "2004-04-19 11:35:00 W. Europe Daylight Time" [4] "2004-04-19 13:35:00 W. Europe Daylight Time" "2004-04-20 07:50:00 W. Europe Daylight Time" > class(my.dt) [1]

I just encountered another RTFM problem: With diff(as.POSIXct(...), ...) I was unable to control the units of the results. Examples: > (d.d <- diff(as.POSIXct(c('2012-12-12', '2012-12-13')))) Time difference of 1 days > (d.h <- diff(as.POSIXct(c('2012-12-12 08:00', '2012-12-12 09:00')))) Time difference of 1 hours > (d.m <-

On Thu, Jun 10, 2010 at 3:39 PM, Gustaf Rydevik <gustaf.rydevik at gmail.com> wrote: > Hi all, > > The recent change in 2.11 that made as.numeric() return false on > difftime-objects broke some of my code that calculated age classes of > individuals using cut(). While this was no big thing to fix for me, it > might be wise > to provide a cut.difftime method to ?stop

On Thu, Jun 10, 2010 at 3:39 PM, Gustaf Rydevik <gustaf.rydevik at gmail.com> wrote: > Hi all, > > The recent change in 2.11 that made as.numeric() return false on > difftime-objects broke some of my code that calculated age classes of > individuals using cut(). While this was no big thing to fix for me, it > might be wise > to provide a cut.difftime method to ?stop

Hello! you, Emil Bode <emil.bode at dans.knaw.nl>, wrote on Tuesday, July 31, 2018 1:55 PM: > Some of the changes you're proposing could be made (with effort), but note that you're not > restricted to providing strings with a format. > What you're trying to do can be accomplished with as.difftime(12, units='weeks'), see also > ?as.difftime > > Or if

Hello again, I'm interested in manipulating some date objects, and have been playing with the difftime function. I'm not sure that this is the desired behavior: > pa$days.before.apr30 <- difftime(may01,as.POSIXct(pa$training.max,origin=as.POSIXct("1969-12-31 16:00:00",tz="PDT")),units="days") > units(pa$days.before.apr30) [1] "days" >

I am trying to write S4 methods with "difftime" in the signature but am being "informed" (? not a warning or error) that "difftime" is not a class. Nevertheless, dispatch takes place. Should I simply ignore that "information"? Here is a toy example: > setClass("foo", contains = "Date") > setMethod("+", c("foo",

R-listers, I have noticed several posts on issues with difftime producing NA's but they have been for older versions of R. Here's the issue associated with difftime that I am dealing with in R 2.12.2. > preciptime = strptime("01/10/2007 14:00",format="%m/%d/%Y %H:%M") > class(preciptime) [1] "POSIXlt" "POSIXt" > # Now using difftime, this

I'm new to R and have the following problem with difftime: if I directly assign date/time strings in difftime I get the expected result: > a<-"2010-03-23 10:52:00" > a [1] "2010-03-23 10:52:00" > b<-"2010-03-23 11:53:00" > u2<-as.difftime(c(a,b), format ="%Y-%m-%d %H:%M:%S", units="mins") > u2 Time differences in mins

It seems that there are several folks Out There with an itch to scratch with respect to difftimes. http://article.gmane.org/gmane.comp.lang.r.devel/19223/match=difftime http://article.gmane.org/gmane.comp.lang.r.devel/18441/match=difftime http://article.gmane.org/gmane.comp.lang.r.devel/10882/match=difftime http://article.gmane.org/gmane.comp.lang.r.devel/11675/match=difftime and I might be

I want to find the DOY (Day of Year) of some dates. I think to substract the date 1. January from the data to achive this. Something like: > d <- as.Date("2006-03-13") - as.Date("2006-01-01") +1 > d Time difference of 72 days So far so good. But d is a 'difftime' object. How do I get an Integer value from that? I tried severel things, incuding the

Hi, I am trying to take difference of two time objects. I want to fix the result's unit to minutes. How can I do that? Here is an example: > difftime(x, y) Time difference of 2.030720 hours > difftime(x, z) Time difference of 30.34672 mins where x = '2007-03-05 08:32:58' y = '2007-03-05 06:31:07' and z = '2007-03-05 08:02:37' How can I get answer

Hello, ?DateTimeClasses states that "one can add or subtract a number of seconds or a 'difftime' object from a date-time object, but not add two date-time objects." So, is the below expected behavior? > x <- Sys.time() > x [1] "2007-02-21 16:19:56 CST" > x + as.difftime("1","%H") [1] "2007-02-21 16:19:57 CST" Warning

Dear all, according to the Help-page of DateTimeClasses {base} I should be able to do time - z with time date-time objects z a numeric vector (in seconds) or an object of class "difftime". However, on R version 2.6.0 (Windows XP) I get > Sys.time() - as.difftime(c("0:3:20", "11:23:15")) Time differences in mins [1] 1191837998 1191837318