| % File src/library/base/man/dim.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2010 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{dim} |
| \alias{dim} |
| \alias{dim.data.frame} |
| \alias{dim<-} |
| \title{Dimensions of an Object} |
| \usage{ |
| dim(x) |
| dim(x) <- value |
| } |
| \description{ |
| Retrieve or set the dimension of an object. |
| } |
| \arguments{ |
| \item{x}{an \R object, for example a matrix, array or data frame.} |
| \item{value}{For the default method, either \code{NULL} or |
| a numeric vector, which is coerced to integer (by truncation).} |
| } |
| \details{ |
| The functions \code{dim} and \code{dim<-} are \link{internal generic} |
| \link{primitive} functions. |
| |
| \code{dim} has a method for \code{\link{data.frame}}s, which returns |
| the lengths of the \code{row.names} attribute of \code{x} and |
| of \code{x} (as the numbers of rows and columns respectively). |
| } |
| \value{ |
| For an array (and hence in particular, for a matrix) \code{dim} retrieves |
| the \code{dim} attribute of the object. It is \code{NULL} or a vector |
| of mode \code{\link{integer}}. |
| |
| The replacement method changes the \code{"dim"} attribute (provided the |
| new value is compatible) and removes any \code{"dimnames"} \emph{and} |
| \code{"names"} attributes. |
| } |
| \references{ |
| Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) |
| \emph{The New S Language}. |
| Wadsworth & Brooks/Cole. |
| } |
| \seealso{ |
| \code{\link{ncol}}, \code{\link{nrow}} and \code{\link{dimnames}}. |
| } |
| \examples{ |
| x <- 1:12 ; dim(x) <- c(3,4) |
| x |
| |
| # simple versions of nrow and ncol could be defined as follows |
| nrow0 <- function(x) dim(x)[1] |
| ncol0 <- function(x) dim(x)[2] |
| } |
| \keyword{array} |