Well, returning 2.0 isn't really an error. The description didn't define the behavior for invalid inputs. From the description, "There is an array with some numbers. All numbers are equal except for one." Your list doesn't match the expectations for this kata, so I'm not sure what you expected to be returned.

Thank you!

You are absolutely correct! Ugh! I have created a couple forks that I believe resolve that bug.

Sorry, it's been so long that I can't remember which language I attempted. I should have noted at the time. Probably JavaScript?

You are absolutely correct! And I admit that didn't even occurred to me until after I submitted my solution. However, for an 8 kyu, I never bothered coming back to write a more careful version, like one that also only iterates over half the characters. But I suppose I could...

Ruby

Thank you!

I've also attempted a Ruby Translation. Please, let me know if it looks alright.

Looks great!

I agree with everyone else, it just needs more tests. And maybe a few random ones.