<string/array> findLast <query>
Would return the index of the last occurrence of the given query in given string or array. -1 if not found.
<query> could also support simple expression
//crappy examples:
"my_string_to_be_searched" findLast "_"; //returns 15
["hello", "faa", 0, "hello", "fii"] findLast "hello"; //returns 3
[[1,2,3], [1,2,3,4], [1,2,3], [1,2,3,4], [1,2,3,4,5,6,7]] findLast {count _x == 4}; // returns 3