谁喜欢这则贴文，初探 case...when 用法，Ruby 30 天刷题修行篇第十六话

嗨，我是 A Fei，让我们看看今天的题目：
（题目来源：Codewars）

You probably know the "like" system from Facebook and other pages. People can "like" blog posts, pictures or other items. We want to create the text that should be displayed next to such an item.

Implement the function which takes an array containing the names of people that like an item. It must return the display text as shown in the examples:

[]                                -->  "no one likes this"
["Peter"]                         -->  "Peter likes this"
["Jacob", "Alex"]                 -->  "Jacob and Alex like this"
["Max", "John", "Mark"]           -->  "Max, John and Mark like this"
["Alex", "Jacob", "Mark", "Max"]  -->  "Alex, Jacob and 2 others like this"

以下是我的答案：

def likes(names)
  case names.size
  when 0
    "no one likes this"
  when 1
    "#{names[0]} likes this"
  when 2
    "#{names[0]} and #{names[1]} like this"
  when 3
    "#{names[0]}, #{names[1]} and #{names[2]} like this"
  else
    "#{names[0]}, #{names[1]} and #{names.size - 2} others like this"
  end  
end

当同一种状况要判断很多次时，可以用 case ... when，让你的 code 更简洁易懂。不过要注意的是，在 case ... when 里面我们是用 === 去判断是否相等，而不是 if ... else 常用的 ==。

由於和最高分解答一模一样，这次就不解析了。