apl: Replacements for APL functions take and drop
In magic: Create and Investigate Magic Squares

Description Usage Arguments Details Author(s) Examples

Replacements for APL functions take and drop

apldrop(a, b, give.indices=FALSE)
apldrop(a, b) <- value
apltake(a, b, give.indices=FALSE)
apltake(a, b) <- value

`a`	Array
`b`	Vector of number of indices to take/drop. Length of `b` should not exceed `length(dim(a))`; if it does, an error is returned
`give.indices`	Boolean, with default `FALSE` meaning to return the appropriate subset of array `a`, and `TRUE` meaning to return the list of the selected elements in each of the dimensions. Setting to `TRUE` is not really intended for the end-user, but is used in the code of `apltake<-()` and `apldrop<-()`
`value`	elements to replace

apltake(a,b) returns an array of the same dimensionality as a. Along dimension i, if b[i]>0, the first b[i] elements are retained; if b[i]<0, the last b[i] elements are retained.

apldrop(a,b) returns an array of the same dimensionality as a. Along dimension i, if b[i]>0, the first b[i] elements are dropped if b[i]<0, the last b[i] elements are dropped.

These functions do not drop singleton dimensions. Use drop() if this is desired.

Robin K. S. Hankin

a <- magichypercube.4n(m=1)
apltake(a,c(2,3,2))
apldrop(a,c(1,1,2))

b <- matrix(1:30,5,6)
apldrop(b,c(1,-2)) <- -1

b <- matrix(1:110,10,11)
apltake(b,2) <- -1
apldrop(b,c(5,-7)) <- -2
b