| difftime {base} | R Documentation |
Create, print and round time intervals.
time1 - time2
difftime(time1, time2, tz = "",
units = c("auto", "secs", "mins", "hours", "days", "weeks"))
as.difftime(tim, format = "%X", units="auto")
## S3 method for class 'difftime':
round(x, digits = 0, ...)
## S3 method for class 'difftime':
format(x, ...)
## S3 method for class 'difftime':
units(x)
## S3 method for class 'difftime':
units(x) <- value
## S3 method for class 'difftime':
as.double(x, units="auto", ...)
time1, time2 |
date-time or date 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. |
value |
character. Like units above, except that
abbreviations are not allowed. |
tim |
character string or numeric value specifying a time interval. |
format |
character specifying the format of tim: see
strptime. The default is a locale-specific time format. |
x |
an object inheriting from class "difftime". |
digits |
integer. Number of significant digits to retain. |
... |
arguments to be passed to or from other methods. |
Function difftime calculates a difference of two date/time objects
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 date-time objects gives an object of this class,
by calling difftime with units="auto". Alternatively,
as.difftime() works on character-coded or numeric time
intervals; in the latter case, units must be specified, and
format has no effect.
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.
The units of a "difftime" object can be extracted by the
units function, which also has an assignment form. If the units
are changed, the numerical value is scaled accordingly.
The as.double method returns the numeric value expressed in
the specified units. Using units="auto" means the units of the
object.
The format method simply formats the numeric value and appends
the units as a text string.
(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
(z <- as.difftime(c(0,30,60), units="mins"))
as.numeric(z, units="secs")
as.numeric(z, units="hours")
format(z)