difftime {base}R Documentation

Time Intervals

Description

Create, print and round time intervals.

Usage

time1 - time2

difftime(time1, time2, tz = "",
         units = c("auto", "secs", "mins", "hours", "days", "weeks"))

as.difftime(tim, format = "%X")

## S3 method for class 'difftime':
round(x, digits = 0)

Arguments

time1, time2 date-time objects.
tz a timezone specification to be used for the conversion. System-specific, but "" is the current time zone, and "GMT" is UTC.
units character. Units in which the results are desired. Can be abbreviated.
tim character string specifying a time interval.
format character specifying the format of tim.
x an object inheriting from class "difftime".
digits integer. Number of significant digits to retain.

Details

Function difftime takes a difference of two date/time objects (of either class) and returns an object of class "difftime" with an attribute indicating the units. There is a round method for objects of this class, as well as methods for the group-generic (see Ops) logical and arithmetic operations.

If units = "auto", a suitable set of units is chosen, the largest possible (excluding "weeks") in which all the absolute differences are greater than one.

Subtraction of two date-time objects gives an object of this class, by calling difftime with units="auto". Alternatively, as.difftime() works on character-coded time intervals.

Limited arithmetic is available on "difftime" objects: they can be added or subtracted, and multiplied or divided by a numeric vector. In addition, adding or subtracting a numeric vector implicitly converts the numeric vector to a "difftime" object with the same units as the "difftime" object.

See Also

DateTimeClasses.

Examples

(z <- Sys.time() - 3600)
Sys.time() - z                # just over 3600 seconds.

## time interval between releases of 1.2.2 and 1.2.3.
ISOdate(2001, 4, 26) - ISOdate(2001, 2, 26)

as.difftime(c("0:3:20", "11:23:15"))
as.difftime(c("3:20", "23:15", "2:"), format= "%H:%M")# 3rd gives NA

[Package base version 2.1.0 Index]