1% Generated by roxygen2: do not edit by hand 2% Please edit documentation in R/coercion.r 3\name{as.duration} 4\alias{as.duration} 5\alias{as.duration,numeric-method} 6\alias{as.duration,logical-method} 7\alias{as.duration,difftime-method} 8\alias{as.duration,Interval-method} 9\alias{as.duration,Duration-method} 10\alias{as.duration,Period-method} 11\alias{as.duration,character-method} 12\title{Change an object to a duration} 13\usage{ 14as.duration(x, ...) 15} 16\arguments{ 17\item{x}{Object to be coerced to a duration} 18 19\item{...}{Parameters passed to other methods. Currently unused.} 20} 21\value{ 22A duration object 23} 24\description{ 25as.duration changes Interval, Period and numeric class objects to 26Duration objects. Numeric objects are changed to Duration objects 27with the seconds unit equal to the numeric value. 28} 29\details{ 30Durations are exact time measurements, whereas periods are relative time 31measurements. See \linkS4class{Period}. The length of a period depends 32on when it occurs. Hence, a one to one mapping does not exist between 33durations and periods. When used with a period object, as.duration provides 34an inexact estimate of the length of the period; each time unit is assigned 35its most common number of seconds. A period of one month is converted to 362628000 seconds (approximately 30.42 days). This ensures that 12 months will 37sum to 365 days, or one normal year. For an exact transformation, first 38transform the period to an interval with \code{\link[=as.interval]{as.interval()}}. 39} 40\examples{ 41span <- interval(ymd("2009-01-01"), ymd("2009-08-01")) #interval 42as.duration(span) 43as.duration(10) # numeric 44dur <- duration(hours = 10, minutes = 6) 45as.numeric(dur, "hours") 46as.numeric(dur, "minutes") 47 48} 49\seealso{ 50\linkS4class{Duration}, \code{\link[=duration]{duration()}} 51} 52\keyword{chron} 53\keyword{classes} 54\keyword{manip} 55\keyword{methods} 56