问题
I love functional programming and I love Ruby as well. If I can code an algorithm in a functional style rather than in a imperative style, I do it. I tend to do not update or reuse variables as much as possible, avoid using "bang!" methods and use "map", "reduce", and similar functions instead of "each" or danger loops, etc. Basically I try to follow the rules of this article.
The problem is that usually the functional solution is much slower that the imperative one. In this article there are clear and scary examples about that, being until 15-20 times slower in some cases. After reading it and doing some benchmarks I am afraid of keep using the functional style, at least in Ruby.
By the other hand I feel more comfortable writing code in functional style because it is smart and clean, it tends to less bugs, and I think is more "correct", specially nowadays that we can use concurrency and parallelism for better performance.
So I am very confused about which style to use in Ruby. Any wise recommendation will be appreciated.
来源：https://stackoverflow.com/questions/22290572/functional-programming-style-vs-performance-in-ruby