One more advice for performance-conscious: prefer

until

to

..

in for loops. In almost every single case it will have the same effect (unless your upper bound can be

Int.MAX_VALUE

, but usually you don't care). That way the generated code would be almost the same as if you had a Java loop such as

for (int i = a; i < b; ++i) { ... }

, and it looks like HotSpot and both Android RTs optimize such loops better.