Combinatorics functions (on arrays) #43175
Description
arrayPermutations( [1,2,3] ) => [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1]]
arrayPartialPermutations( [1,2,3], 2 ) => [ [1,2], [1,3], [2,1], [2,3], [3,1], [3,2]]
arrayCombinations( [1,2,3], 2 ) => ( [1,2], [1,3], [2,3] )
maybe also factorial function to simplify some counts