% File src/library/base/man/round.POSIXt.Rd
% Part of the R package, http://www.R-project.org
% Copyright 1995-2007 R Core Development Team
% Distributed under GPL 2 or later

\name{round.POSIXt}
\alias{round.POSIXt}
\alias{trunc.POSIXt}
\alias{round.Date}
\alias{trunc.Date}
\title{Round / Truncate Data-Time Objects}
\description{
  Round or truncate date-time objects.
}
\usage{
\method{round}{POSIXt}(x, units = c("secs", "mins", "hours", "days"))
\method{trunc}{POSIXt}(x, units = c("secs", "mins", "hours", "days"), \dots)

\method{round}{Date}(x, \dots)
\method{trunc}{Date}(x, \dots)
}
\arguments{
  \item{x}{an object inheriting from \code{"POSIXt"} or \code{"Date"}.}
  \item{units}{one of the units listed.  Can be abbreviated.}
  \item{\dots}{arguments to be passed to or from other methods, notably
    \code{digits} for \code{round}.}
}
\details{
  The time is rounded or truncated to the second, minute, hour or day.
  Timezones are only relevant to days, when midnight in the current
  timezone is used.

  The methods for class \code{"Date"} are of little use except to remove
  fractional days.
}
\value{
  An object of class \code{"POSIXlt"} or \code{"Date"}.
}
\seealso{
  \code{\link{round}} for the generic function and default methods.
  
  \code{\link{DateTimeClasses}}, \code{\link{Date}}
}

\examples{
round(.leap.seconds + 1000, "hour")
trunc(Sys.time(), "day")
}
\keyword{chron}