This is a continuation of ArraysCowan, put on a separate page for convenience.
These procedures are mostly derived in function, and sometimes in name, from ISO/IEC 8485 and ISO 17351, which standardize basic and extended APL respectively.
(array-collapse array j)
Let k be the rank of array. This procedure returns an array of rank j, which MUST be less than or equal to k, whose components are arrays of rank k - j. The shape of the returned array is equal to the first j components of the shape of array, and the shapes of its subarrays are equal to the remaining k-j components.
(array-explode array j)
Let k be the rank of array. This procedure constructs and returns an array of rank j, which MUST be greater than or equal to k. Each component of array MUST be an array of rank j - k, all of which MUST have the same shape. The shape of the returned array is the shape of array concatenated with the shape of any of its components, and each component is the corresponding component of the corresponding subarray of array.
(array-reshape shape array)
Constructs and returns a new array of shape shape whose components in row-major order are the same (in the sense of eqv?) as the components of array in row-major order.
(array-reverse array axis)
Constructs and returns a new array with the same shape as array, but whose elements on the specified axis are reversed. Axis must be a non-negative integer less than the rank of array.
(array-reverse! array axis)
Overwrites array with the value of (array-reverse array axis), but without allocating storage.
(array-compress array booleans axis)
(array-expand array booleans nil axis)
(array-rearrange array vector axis)
(array-rearrange-axes array vector)
(subarray array start-subscripts end-subscripts)
(array-recursive-ref array subscript ...)
Apply array-ref to the array using the first i subscripts, where i is the rank of array. If there are more subscripts, the result MUST be an array. Apply array-ref to the result using the next j subscripts, where j is the rank of the result. Repeat until there are no more subscripts, returning the last result.
These procedures are mostly derived in function, and sometimes in name, from ISO/IEC 8485 and ISO 17351, which standardize basic and extended APL respectively.
(array-reduce proc array axis)
Construct and return a new array whose rank is one less than the rank of array, by combining all the elements along axis using proc, which MUST be a two-argument procedure. The order and number of invocations of proc is unspecified. If there is only one such element, it is unchanged.
(array-reduce-subarrays proc array axis n)
Construct and return a new array with the same rank as the rank of array, by combining all the groups of elements of length n along axis using proc, which MUST be a two-argument procedure. The order and number of invocations of proc is unspecified. If there is only one such group of elements, it is unchanged.
(array-scan proc array axis)
Construct and return a new array whose shape is the same as the shape of array. Each element along axis is constructed by reducing (as if by array-reduce) successive prefixes of the elements of array along that axis.
(array-outer-product proc array1 array2)
Construct and return a new array whose shape is the concatenation of the shapes of array1 and array2. Each component of the new array is the result of applying proc to every element of array1 and every element of array2 in unspecified order. The order and number of invocations of proc is unspecified.
(array-inner-product proc1 proc2 array1 array2)