I think you probably want
format='%m/%d/%y %H:%M')
(lower case "y")
diff() as suggested by Jeff Newmiller is good, except that I don't know
how to control the units using diff().
## so a method that allows specifying units other than hours would be, for
example,
datetime <-c("1/1/13 00:00","1/1/13 12:00","1/2/13 00:00","1/2/13 12:00")
datetime <-as.POSIXct(datetime,format='%m/%d/%y %H:%M')deltas <- difftime(
datetime[-1], datetime[-length(datetime)] , units='min')
-Don
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
On 5/10/13 10:24 AM, "Andras Farkas" <motyoc...@yahoo.com> wrote:
>Dear All
>
>I have the following code:
>
>datetime <-c("1/1/13 00:00","1/1/13 12:00","1/2/13 00:00","1/2/13 12:00")
>datetime <-as.POSIXct(datetime,format='%m/%d/%Y %H:%M')
>times
><-matrix(c(difftime(datetime[2],datetime[1],units="hours"),difftime(dateti
>me[3],datetime[2],units="hours"),difftime(datetime[4],datetime[3],units="h
>ours")))
>
>I would like to aks for some directions on how to make the 'times' object
>code a bit more "uniform" to accept differenth lenths of 'datetime'...
>Occasionally I have the 'datetime' object include up to 15 date and time
>points, but that code limits the system from accepting a longer
>'datetime' object. This is what that looks like (basically same as above,
>but much longer):
>
>datetime <-c("1/1/13 00:00","1/1/13 12:00","1/2/13 00:00","1/2/13 12:00")
>datetime <-as.POSIXct(datetime,format='%m/%d/%Y %H:%M')
>times
><-matrix(c(difftime(datetime[2],datetime[1],units="hours"),difftime(dateti
>me[3],datetime[2],units="hours"),difftime(datetime[4],datetime[3],units="h
>ours"),difftime(datetime[5],datetime[4],units="hours"),difftime(datetime[6
>],datetime[5],units="hours"),difftime(datetime[7],datetime[6],units="hours
>"),difftime(datetime[8],datetime[7],units="hours"),difftime(datetime[9],da
>tetime[8],units="hours"),difftime(datetime[10],datetime[9],units="hours"),
>difftime(datetime[11],datetime[10],units="hours"),difftime(datetime[12],da
>tetime[11],units="hours"),difftime(datetime[13],datetime[12],units="hours"
>),difftime(datetime[14],datetime[13],units="hours"),difftime(datetime[15],
>datetime[14],units="hours"),difftime(datetime[16],datetime[15],units="hour
>s")))
>
>appreciate the help,
>
>Andras
> [[alternative HTML version deleted]]
>
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