[Rd] diff(time) vs. difftime?
spencer.graves at structuremonitoring.com
Mon Mar 19 23:27:10 CET 2012
I just encountered another RTFM problem: With
diff(as.POSIXct(...), ...) I was unable to control the units of the
> (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 <- diff(as.POSIXct(c('2012-12-12 08:00', '2012-12-12 08:01'))))
Time difference of 1 mins
> (d.s <- diff(as.POSIXct(c('2012-12-12 08:00:00', '2012-12-12
Time difference of 1 secs
methods('diff') identified the following:
 diff.Date diff.default diff.POSIXt diff.ts diff.zoo*
In looking at the help pages for each of these functions, I found
no mention of "difftime" or any other way to control the units.
 -.Date -.POSIXt -.yearmon* -.yearqtr*
?"-.Date" didn't seem helpful on this, either. ?"-.POSIXt"
contained a link to "difftime", but I didn't see that until after I read
the code for "-.POSIXt" and found "difftime".
I humbly beseech ye to consider adding a difftime example to all
these help pages.
p.s. In case there is any doubt, I very much appreciate all the work
that the R Core team has invested in making R what it is today.
Spencer Graves, PE, PhD
President and Chief Technology Officer
Structure Inspection and Monitoring, Inc.
751 Emerson Ct.
San José, CA 95126
More information about the R-devel