The R Project SVN R

\name{terms.formula}
\alias{terms.formula}
%- Also NEED an `\alias' for EACH other topic documented here.
\title{A function to construct a terms object from a formula. }
\description{
  This function takes a formula and some optional arguments and
  constructs a terms object. The terms object can then be used to
  construct a \code{\link{model.matrix}}.
}
\usage{
terms.formula(x, specials=NULL, abb=NULL, data=NULL, neg.out=TRUE, keep.order=FALSE)
}
%- maybe also `usage' for other objects documented here.
\arguments{
  \item{x}{A formula. }
  \item{specials}{What functions in the formula should be marked as
    special in the terms object. }
  \item{abb}{Unused in R. }
  \item{data}{A data frame from which the meaning of the special symbol
    \code{.} can be inferred. It is unused if there is no \code{.} in
    the formula. }
  \item{neg.out}{TRUE if terms with a minus, \code{-} should be removed.
  If FALSE these are kept in an indicate a negative order (for fractionate?).}
  \item{keep.order}{A logical value indicating whether the terms should
    keep their positions. If FALSE the terms are reordered so that main
    effects come first. }
}
\details{
  Not all of the options work in the same way that they do in S and not
  all are implemented.
}
\value{
  A \code{\link{terms}} object is returned.
}
\seealso{ \code{\link{terms.object}},  \code{\link{terms.default}} }
\keyword{ models }%-- one or more ...