œ? - Permutation At Index
Tags: miscellaneous , array , combinatorics
This atom is dyadic, which means it takes two arguments.
xth permutation of
x œ? y is equivalent to
y Œ! x ị (but much more efficient, as it does not have to generate all
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):