| % File src/library/grDevices/man/extendrange.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2018 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{extendrange} |
| \alias{extendrange} |
| \title{Extend a Numerical Range by a Small Percentage} |
| \description{ |
| Extends a numerical range by a small percentage, i.e., fraction, |
| \emph{on both sides}. |
| } |
| \usage{ |
| extendrange(x, r = range(x, na.rm = TRUE), f = 0.05) |
| } |
| \arguments{ |
| \item{x}{numeric vector; not used if \code{r} is specified.} |
| \item{r}{numeric vector of length 2; defaults to the |
| \code{\link{range}} of \code{x}.} |
| \item{f}{positive number(s) specifying the fraction by which the range should be |
| extended. If longer than one, \code{f[1]} is used on the left, and |
| \code{f[2]} on the right.} |
| } |
| \seealso{\code{\link{range}}; \code{\link{pretty}} which can be |
| considered a sophisticated extension of \code{extendrange}. |
| } |
| \value{ |
| A numeric vector of length 2, \code{r + c(-f1,f2) * diff(r)}, where |
| f1 is \code{f[1]} and f2 is \code{f[2]} or \code{f} if it is of length |
| one. |
| } |
| \examples{ |
| x <- 1:5 |
| (r <- range(x)) # 1 5 |
| extendrange(x) # 0.8 5.2 |
| extendrange(x, f= 0.01) # 0.96 5.04 |
| |
| ## extend more to the right: |
| extendrange(x, f=c(.01,.03)) # 0.96 5.12 |
| |
| ## Use 'r' if you have it already: |
| stopifnot(identical(extendrange(r = r), |
| extendrange(x))) |
| } |
| \keyword{dplot} |