Time Intervals

difftime

Time Intervals

Description

The class difftime represents time intervals.

Usage

.difftime(xx, units) # generally for internal use
difftime(time1, time2, tz, units = c("auto", "secs", "mins", 
   "hours", "days", "weeks"))
## S3 method for class 'difftime':
print(x, digits = getOption("digits"), ...)
## S3 method for class 'difftime':
[(x, ..., drop = TRUE)
## S3 method for class 'difftime':
c(..., recursive = FALSE)
## S3 method for class 'difftime':
diff(x, lag = 1L, differences = 1L)

Arguments

xx	an S object.
time1, time2	an S object that is inherited from or can be converted to POSIXt, such as POSIXct or POSIXlt objects or date-time strings.
tz	a character string representing the time zone, such as "GMT".
units	a character string from "auto", "secs", "mins", "hours", "days", and "weeks".
format	a character string representing the time format for tim.
x	a difftime object.
digits	the maximum number of (significant) digits to print.
drop	a logical flag passed to operator [.
lag	a positive integer, the spacing of the entries to difference
differences	a positive integer, the number of iterations of differencing
...	additional arguments.

Details

A difftime object is internally represented as structure(i, units = "hours", class = "difftime"), where i is numeric representing the number of units.

Value

.difftime	returns a difftime object with specified units.
difftime	returns a difftime object representing the time difference between time1 and time2.
print.difftime	returns the original object x, with the invisible flag set to prevent reprinting.
[.difftime	returns a difftime object formed by extracting the relevant subset.
c.difftime	returns a difftime object formed by the concatenation of all of its inputs (except recursive, which is ignored). If the units of all of the difftime inputs are the same, then it is the units of the output. If the units differ or if no inputs are difftime objects, then the output units are "secs".
diff.difftime	returns a difftime object with the units of x and values diff(as.numeric(x), lag, differences)

Differences between Spotfire Enterprise Runtime for R and Open-source R

Differences exist between Spotfire Enterprise Runtime for R and open-source R in the results for calculating difftime near DST; the Spotfire Enterprise Runtime for R results appear more reasonable than those of open-source R.

Example

## The start of DST in USA 2013 is 2013-03-10 2:00AM > difftime("2013-03-10 03:00:00", "2013-03-10 02:00:00", tz = "America/New_York") # Time difference of 2 hours (open-source R) # Time difference of 0 secs (TERR) > difftime("2013-03-10 03:00:00", "2013-03-10 02:59:00", tz = "America/New_York") # Time difference of 2 hours (open-source R) # Time difference of -59 mins (TERR) The differences are caused by the differences in as.POSIXct, i.e., > as.POSIXct("2013-03-10 02:00:00", tz = "America/New_York") # [1] "2013-03-10 EST" (open-source R) # [1] "2013-03-10 03:00:00 EDT" (TERR) > as.POSIXct("2011-03-13 02:59:59", tz = "America/New_York") # [1] "2013-03-10 EST" (open-source R) # [1] "2013-03-10 03:59:59 EDT" (TERR)