Atom - œ? - Permutation At Index

Characters: œ , ?

Tags: miscellaneous , array , combinatorics

Arity: dyadic

This atom is dyadic, which means it takes two arguments.


Return the xth permutation of y.


x œ? y is equivalent to y Œ! x ị (but much more efficient, as it does not have to generate all len(y)! permutations).


This atom should work roughly the same way as or very similarly in concept to the following code snippets (some edge case exceptions may exist):