% File src/library/base/man/sign.Rd
% Part of the R package, http://www.R-project.org
% Copyright 1995-2010 R Core Team
% Distributed under GPL 2 or later

\name{sign}
\title{Sign Function}
\usage{
sign(x)
}
\alias{sign}
\arguments{
  \item{x}{a numeric vector}
}
\description{
  \code{sign} returns a vector with the signs of the corresponding
  elements of \code{x} (the sign of a real number is 1, 0, or \eqn{-1}
  if the number is positive, zero, or negative, respectively).

  Note that \code{sign} does not operate on complex vectors.
}
\details{
  This is an \link{internal generic} \link{primitive} function: methods
  can be defined for it directly or via the
  \code{\link[=S3groupGeneric]{Math}} group generic.
}
\seealso{
  \code{\link{abs}}
}
\examples{
sign(pi)    # == 1
sign(-2:3)  # -1 -1 0 1 1 1
}
\keyword{arith}