First non-singleton dimension

Given an array, returns the first non-singleton dimension. Useful for emulating some of Matlab / Octave's multidimensional functions.

If n is supplied, return the first n nonsingleton dimensions.

Usage

fnsd(a,n)

Arguments

a

An array

n

Integer. Return the first n nonsingleton dimensions

Value

Returns an integer vector with elements in the range 1 to length(dim(a)).

Author

Robin K. S. Hankin

Note

Treats zero-extent dimensions as singletons.

Case n=0 now treated sensibly (returns a zero-length vector).

See also

arev

Examples

a <- array(1:24,c(1,1,1,1,2,1,3,4))
fnsd(a)
#> [1] 5
fnsd(a,2)
#> [1] 5 7