ID EN
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Math Functions

difftime

R Base 3.6.2

Time intervals creation, printing, and some arithmetic. The print() method calls these “time differences”.

Syntax

R 
<code>time1 - time2</code><p></p><p>difftime(time1, time2, tz,
         units = c("auto", "secs", "mins", "hours",
                   "days", "weeks"))</p><p>as.difftime(tim, format = "%X", units = "auto")</p><p># S3 method for difftime
format(x, ...)
# S3 method for difftime
units(x)
# S3 method for difftime
units(x) &lt;- value
# S3 method for difftime
as.double(x, units = "auto", ...)</p><p>## Group methods, notably for round(), signif(), floor(),
## ceiling(), trunc(), abs(); called directly, *not* as Math():
# S3 method for difftime
Math(x, &#8230;)</p>

Arguments

Parameter Description
time1, time2 date-time or date objects.
tz an optional time zone specification to be used for the conversion, mainly for "POSIXlt" objects.
units character string. Units in which the results are desired. Can be abbreviated.
value character string. Like units, 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".
&#8230; arguments to be passed to or from other methods.

Details

Function difftime calculates a difference of two date/time objects and returns an object of class "difftime" with an attribute indicating the units. The Math group method provides round, signif, floor, ceiling, trunc, abs, and sign methods for objects of this class, and there are 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

Examples

Example
R 
# NOT RUN {
(z <- Sys.time() - 3600)
Sys.time() - z                # just over 3600 seconds.

## time interval between release days of R 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)
# }

See Also

DateTimeClasses.