| adrop {abind} | R Documentation |
Drop degenerate dimensions of an array object. Offers more control
than the drop() function.
adrop(x, drop = TRUE, named.vector = TRUE, one.d.array = FALSE)
x |
An array (including a matrix) |
drop |
A logical or numeric vector describing the dimensions to be dropped. |
named.vector |
(Optional, defaults to TRUE. Controls
whether a vector result has names derived from the dimnames
of x. |
one.d.array |
(Optional, defaults to FALSE. If
TRUE, a one-dimensional array result will be an object with a
dim attribute of
length 1, and possibly a dimnames attribute. If
FALSE, a one-dimensional result will be a vector object
(named if named.vector==TRUE). |
Dimensions can only be dropped if their extent is one, i.e., dimension
i of array x can be dropped only if dim(x)[i]==1.
It is an error to request adrop to drop a dimension whose
extent is not 1.
If x is an object with a dim attribute (e.g., a matrix or
array), then adrop returns an object like x,
but with the requested
extents of length one removed. Any accompanying dimnames
attribute is adjusted and returned with x.
Tony Plate tplate@acm.org
x <- array(1:24,dim=c(2,3,4),dimnames=list(letters[1:2],LETTERS[1:3],letters[23:26])) adrop(x[1,,,drop=FALSE],drop=1) adrop(x[,1,,drop=FALSE],drop=2) adrop(x[,,1,drop=FALSE],drop=3) adrop(x[1,1,1,drop=FALSE],drop=1) adrop(x[1,1,1,drop=FALSE],drop=2) adrop(x[1,1,1,drop=FALSE],drop=3) adrop(x[1,1,1,drop=FALSE],drop=1:2) adrop(x[1,1,1,drop=FALSE],drop=1:2,one.d=TRUE) adrop(x[1,1,1,drop=FALSE],drop=1:2,named=FALSE) dim(adrop(x[1,1,1,drop=FALSE],drop=1:2,one.d=TRUE)) dimnames(adrop(x[1,1,1,drop=FALSE],drop=1:2,one.d=TRUE)) names(adrop(x[1,1,1,drop=FALSE],drop=1:2,one.d=TRUE)) dim(adrop(x[1,1,1,drop=FALSE],drop=1:2)) dimnames(adrop(x[1,1,1,drop=FALSE],drop=1:2)) names(adrop(x[1,1,1,drop=FALSE],drop=1:2))