.. _library_combinations:

combinations

This library provides predicates for generating and querying combinations over lists. The following categories of predicates are provided:

• Generation operations - Predicates for generating combinations, including combinations with replacement.
• Ordering variants - Predicates that support an additional order argument (default, lexicographic, or shortlex) for controlling output order.
• Distinct-value generation - Predicates for generating combinations while deduplicating equal-valued results.
• Indexed access - Predicates for direct access to combinations at specific positions.
• Counting operations - Predicates for counting combinations with and without replacement.
• Random selection - Predicates for randomly selecting combinations. Dedicated subsequences and permutations libraries are also available for focused APIs on those operations.

API documentation

Open the `../../apis/library_index.html#combinations <../../apis/library_index.html#combinations>`__ link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

::

| ?- logtalk_load(combinations(loader)).

Testing

To test this library predicates, load the tester.lgt file:

::

| ?- logtalk_load(combinations(tester)).