I like that version A 1) is more readable (fight me) 2) doesn't rely on internal optimizations for string concatenation, in order to be as efficient 3) doesn

I like that version A 1) is more readable (fight me) 2) doesn't rely on internal optimizations for string concatenation, in order to be as efficient 3) doesn't create extra garbage (linked lists) In fact, the only thing I would change is make it a for loop instead.