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\name{irts}
\alias{irts}
\alias{is.irts}
\alias{as.irts}
\alias{as.irts.default}
\alias{as.irts.zoo}
\title{Irregularly Spaced Time-Series}
\description{
The function \code{irts} is used to create irregular time-series
objects.
\code{as.irts} coerces an object to an irregularly spaced
time-series. \code{is.irts} tests whether an object is an irregularly
spaced time series.
}
\usage{
irts(time, value)
as.irts(object)
is.irts(object)
}
\arguments{
\item{time}{a numeric vector or a vector of class \code{"POSIXct"}
representing the time-stamps of the irregular time-series
object. The elements of the numeric vector are construed as the
(signed) number of seconds since the beginning of 1970, see
\code{\link{POSIXct}}.}
\item{value}{a numeric vector or matrix representing the values of the
irregular time-series object.}
\item{object}{an R object to be coerced to an irregular time-series
object or an R object to be tested whether it is an irregular
time-series object.}
}
\details{
The function \code{irts} is used to create irregular time-series
objects. These are scalar or vector valued time series indexed by a
time-stamp of class \code{"POSIXct"}. Unlike objects of class
\code{"ts"}, they can be used to represent irregularly spaced
time-series.
}
\value{
A list of class \code{"irts"} with the following elements:
\item{time}{a vector of class \code{"POSIXct"}.}
\item{value}{a numeric vector or matrix.}
}
\author{
A. Trapletti
}
\seealso{
\code{\link{ts}},
\code{\link{POSIXct}},
\code{\link{irts-methods}},
\code{\link{irts-functions}}
}
\examples{
n <- 10
t <- cumsum(rexp(n, rate = 0.1))
v <- rnorm(n)
x <- irts(t, v)
x
as.irts(cbind(t, v))
is.irts(x)
# Multivariate
u <- rnorm(n)
irts(t, cbind(u, v))
}
\keyword{ts}
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