Drop degenerate dimensions of an array object. Offers less
automaticity and more control than the base drop() function.
adrop() is a S3 generic, with one method, adrop.default,
supplied in the abind package.
Usage
adrop(x, drop = TRUE, named.vector = TRUE, one.d.array = FALSE)
Arguments
x
An array (including a matrix)
drop
A logical or numeric vector describing exactly which dimensions to
drop. It is intended that this argument be supplied always. The
default is very rarely useful (drop=TRUE means drop the first
dimension of a 1-d array).
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).
Details
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.
A 1-d array can be converted to a named vector by supplying
drop=NULL (which means drop no dimensions, and return a 1-d
array result as a named vector).
Value
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.