| % File src/library/stats/man/relevel.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2007, 2016 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{relevel} |
| \alias{relevel} |
| \alias{relevel.default} |
| \alias{relevel.factor} |
| \alias{relevel.ordered} |
| \title{Reorder Levels of Factor} |
| \usage{ |
| relevel(x, ref, \dots) |
| } |
| \arguments{ |
| \item{x}{an unordered factor.} |
| \item{ref}{the reference level, typically a string.} |
| \item{\dots}{additional arguments for future methods.} |
| } |
| \description{ |
| The levels of a factor are re-ordered so that the level specified by |
| \code{ref} is first and the others are moved down. This is useful |
| for \code{contr.treatment} contrasts which take the first level as |
| the reference. |
| } |
| \value{ |
| A factor of the same length as \code{x}. |
| } |
| \details{ |
| This, as \code{\link{reorder}()}, is a special case of simply calling |
| \code{\link{factor}(x, levels = levels(x)[....])}. |
| } |
| \seealso{ |
| \code{\link{factor}}, \code{\link{contr.treatment}}, |
| \code{\link{levels}}, \code{\link{reorder}}. |
| } |
| |
| \examples{ |
| warpbreaks$tension <- relevel(warpbreaks$tension, ref = "M") |
| summary(lm(breaks ~ wool + tension, data = warpbreaks)) |
| } |
| \keyword{utilities} |
| \keyword{models} |