round.POSIXt {base}R Documentation

Round / Truncate Date-Time Objects

Description

Round or truncate date-time objects.

Usage

## S3 method for class 'POSIXt'
round(x,
      units = c("secs", "mins", "hours", "days", "months", "years"))
## S3 method for class 'POSIXt'
trunc(x,
      units = c("secs", "mins", "hours", "days", "months", "years"),
      ...)

## S3 method for class 'Date'
round(x, ...)
## S3 method for class 'Date'
trunc(x,
      units = c("secs", "mins", "hours", "days", "months", "years"),
      ...)

Arguments

x

an object inheriting from "POSIXt" or "Date".

units

one of the units listed, a string. Can be abbreviated.

...

arguments to be passed to or from other methods, notably digits for round.

Details

The time is rounded or truncated to the second, minute, hour, day, month or year. Time zones are only relevant to days or more, when midnight in the current time zone is used.

For units arguments besides “months” and “years”, the methods for class "Date" are of little use except to remove fractional days.

Value

An object of class "POSIXlt" or "Date".

See Also

round for the generic function and default methods.

DateTimeClasses, Date

Examples

round(.leap.seconds + 1000, "hour")

         trunc(Sys.time(), "day")
(timM <- trunc(Sys.time() -> St, "months")) # shows timezone
(datM <- trunc(Sys.Date() -> Sd, "months"))
(timY <- trunc(St, "years")) # + timezone
(datY <- trunc(Sd, "years"))

stopifnot(inherits(datM, "Date"), inherits(timM, "POSIXt"),
          substring(format(datM), 9,10) == "01", # first of month
          substring(format(datY), 6,10) == "01-01", # Jan 1
          identical(format(datM), format(timM)),
          identical(format(datY), format(timY)))
[Package base version 4.4.1 Index]