| % File src/library/base/man/drop.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2008 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{drop} |
| \alias{drop} |
| \title{Drop Redundant Extent Information} |
| \description{ |
| Delete the dimensions of an array which have only one level. |
| } |
| \usage{ |
| drop(x) |
| } |
| \arguments{ |
| \item{x}{an array (including a matrix).} |
| } |
| \value{ |
| If \code{x} is an object with a \code{dim} attribute (e.g., a matrix |
| or \code{\link{array}}), then \code{drop} returns an object like |
| \code{x}, but with any extents of length one removed. Any |
| accompanying \code{dimnames} attribute is adjusted and returned with |
| \code{x}: if the result is a vector the \code{names} are taken from |
| the \code{dimnames} (if any). If the result is a length-one vector, |
| the names are taken from the first dimension with a dimname. |
| |
| Array subsetting (\code{\link{[}}) performs this reduction unless used |
| with \code{drop = FALSE}, but sometimes it is useful to invoke |
| \code{drop} directly. |
| } |
| \seealso{ |
| \code{\link{drop1}} which is used for dropping terms in models. |
| } |
| \examples{ |
| dim(drop(array(1:12, dim = c(1,3,1,1,2,1,2)))) # = 3 2 2 |
| drop(1:3 \%*\% 2:4) # scalar product |
| } |
| \keyword{array} |