Ruby factorial function

Question

I\'m going crazy: Where is the Ruby function for factorial? No, I don\'t need tutorial implementations, I just want the function from the library. It\'s not in Math!

Answer 1

Here is my version seems to be clear to me even though it's not as clean.

def factorial(num)
    step = 0
    (num - 1).times do (step += 1 ;num *= step) end
    return num
end

This was my irb testing line that showed each step.

num = 8;step = 0;(num - 1).times do (step += 1 ;num *= step; puts num) end;num