Return a corner of an array object (like head)

Return a small corner of an array object, like head() or tail() but taking only a few slices on each dimension.

acorn(x, n=6, m=5, r=1, ...)

Arguments

x

An array (including a matrix or a data frame)

n,m,r

Numbers of items on each dimension. A negative number is interpreted as this many items at the end (like tail).

...

Further arguments specifying numbers of slices to return on each dimension.

Details

Like head() for multidimensional arrays, with two differences: (1) returns just a few items on each dimension, and (2) negative numbers are treated like tail().

Value

An object like x with fewer elements on each dimension.

Author

Tony Plate tplate@acm.org

Examples

x <- array(1:24,dim=c(4,3,2),dimnames=rev(list(letters[1:2],LETTERS[1:3],letters[23:26])))
acorn(x)
#> , , a
#> 
#>   A B  C
#> w 1 5  9
#> x 2 6 10
#> y 3 7 11
#> z 4 8 12
#> 
acorn(x, 3)
#> , , a
#> 
#>   A B  C
#> w 1 5  9
#> x 2 6 10
#> y 3 7 11
#> 
acorn(x, -3)
#> , , a
#> 
#>   A B  C
#> x 2 6 10
#> y 3 7 11
#> z 4 8 12
#> 
acorn(x, 3, -2)
#> , , a
#> 
#>   B  C
#> w 5  9
#> x 6 10
#> y 7 11
#>