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collection_to_array(+Collection, -List)

Convert a "collection" into a list
Collection
A term to be interpreted as a collection
List
Output array

Description

Converts various "collection" data structures into an array. Fails if it does not know how to do this. The supported collection types are:
List
The list is converted into an array using array_list/2.
Array
The array is returned unchanged.
Subscript reference Array[...]
subscript/3 is called to evaluate the subscript reference. If this results in a single array element, a one-element array is returned. If subscript/3 results in a sub-array, this is returned.
flatten(N, Collection)
If the collection is nested (multi-dimensional), the top N nesting levels of the structure are converted into a flat array.
flatten(Collection)
If the collection is nested (multi-dimensional), all nesting structure is removed and a flat array is returned. All subterms that look like list or array will be interpreted as such (including []).

Modes and Determinism

Fail Conditions

Collection is not a collection

Examples

   ?- collection_to_array([a,b,[c,d]], Array).
   Array = [](a, b, [c, d])
   Yes
   ?- collection_to_array(flatten([a,b,[c,d]]), Array).
   Array = [](a, b, c, d)
   Yes
   ?- collection_to_array(flatten([](a,b,[c,d])), Array).
   Array = [](a, b, c, d)
   Yes
   ?- A = []([](a,b,c),[](d,e,f)),
      collection_to_array(flatten(A[1..2,2..3]), Array).
   Array = [](b, c, e, f)
   Yes
   ?- L = [[a,b],[[c,d],[e,f]],g],
      collection_to_array(flatten(1, L), Array).
   Array = [](a, b, [c, d], [e, f], g)
   Yes

See Also

collection_to_list / 2, subscript / 3, array_flat / 3