\name{lag}


\title{Lag a Time Series}


\alias{lag}
\alias{lag.timeSeries} 


\description{
    
    Compute a lagged version of a 'timeSeries' object.        
   
}


\usage{
\method{lag}{timeSeries}(x, k = 1, trim = FALSE, units = NULL, \dots)
}


\arguments{
         
    \item{k}{   
        [lagSeries] - \cr   
        an integer value. The number of lags (in units of observations).
        By default 1.
        }        
    \item{trim}{
        a logical value. By default \code{TRUE}, the first missing 
        observation in the return series will be removed. 
        }
    \item{units}{
        an optional character string, which allows to overwrite the 
        current column names of a \code{timeSeries} object. By default 
        \code{NULL} which means that the column names are selected
        automatically.
        }
    \item{x}{
        an object of class \code{timeSeries}.
        } 
    \item{\dots}{
        arguments passed to other methods.
        }
       
}


\value{

    returns a lagged S4 object of class \code{timeSeries}.
        
}


\examples{
## data - 
   x = as.timeSeries(data(msft.dat))[1:20, "Open"]
   
## lag -
   # Lag the timeSeries Object:
   lag(x, k = -1:1)
}


\keyword{chron}