| % File src/library/base/man/diff.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2011 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{diff} |
| \alias{diff} |
| \alias{diff.default} |
| \alias{diff.POSIXt} |
| \alias{diff.Date} |
| \concept{difference} |
| \title{Lagged Differences} |
| \description{ |
| Returns suitably lagged and iterated differences. |
| } |
| \usage{ |
| diff(x, \dots) |
| |
| \method{diff}{default}(x, lag = 1, differences = 1, \dots) |
| |
| \method{diff}{POSIXt}(x, lag = 1, differences = 1, \dots) |
| |
| \method{diff}{Date}(x, lag = 1, differences = 1, \dots) |
| } |
| \arguments{ |
| \item{x}{a numeric vector or matrix containing the values to be |
| differenced.} |
| \item{lag}{an integer indicating which lag to use.} |
| \item{differences}{an integer indicating the order of the difference.} |
| \item{\dots}{further arguments to be passed to or from methods.} |
| } |
| \details{ |
| \code{diff} is a generic function with a default method and ones for |
| classes \code{"\link{ts}"}, \code{"\link{POSIXt}"} and |
| \code{"\link{Date}"}. |
| |
| \code{\link{NA}}'s propagate. |
| } |
| \value{ |
| If \code{x} is a vector of length \code{n} and \code{differences = 1}, |
| then the computed result is equal to the successive differences |
| \code{x[(1+lag):n] - x[1:(n-lag)]}. |
| |
| If \code{difference} is larger than one this algorithm is applied |
| recursively to \code{x}. |
| Note that the returned value is a vector which is shorter than |
| \code{x}. |
| |
| If \code{x} is a matrix then the difference operations are carried out |
| on each column separately. |
| } |
| \references{ |
| Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) |
| \emph{The New S Language}. |
| Wadsworth & Brooks/Cole. |
| } |
| \seealso{ |
| \code{\link{diff.ts}}, \code{\link{diffinv}}. |
| } |
| \examples{ |
| diff(1:10, 2) |
| diff(1:10, 2, 2) |
| x <- cumsum(cumsum(1:10)) |
| diff(x, lag = 2) |
| diff(x, differences = 2) |
| |
| diff(.leap.seconds) |
| } |
| \keyword{arith} |