如何使用 case 语句遍历对象数组并将值添加到数组内的键？

Question

我想使用 case 语句查看一组对象，并向键名添加一个新值。我是编程新手，请使用最简单的示例和解释。

我尝试编写一个 case 语句，使用等号运算符将新值添加到键名。

beatles = [
    {
      name: nil,
      nickname: "The Smart One"
    },
    {
      name: nil,
      nickname: "The Funny One"
    },
    {
      name: nil,
      nickname: "The Cute One"
      },
    {
      name: nil,
      nickname: "The Quiet One"
    }
  ]

  i = 0
  while i < beatles.length
    case beatles
    when nickname == "The Smart One"
        name = "John"
    when nickname == "The Funny One"
        name = "Ringo"
    when nickname == "The Cute One"
        name = "Paul"
    when nickname == "The Quiet One"
        name = "George"
    end
    i += 1
  end

  i = 0
  while i < beatles.length
    puts "Hi, I'm #{beatles[i][:name]}.  I'm #{beatles[i][:nickname]}!"
    i += 1
  end

Answer 1

没有人在 Ruby 中使用 while 循环（我们使用 Enumerable#each、Enumerable#map 和 Enumerable#reduce，）但是为了回答此处陈述的问题是请求的版本。

while i < beatles.length
  beatles[i][:name] =
    case beatles[i][:nickname]
    when "The Smart One" then "John"
    when "The Funny One" then "Ringo"
    when "The Cute One" then "Paul"
    when "The Quiet One" then "George"
    end
  i += 1
end

case 将其参数与变体进行比较（使用 Object#=== 方法。）此外，您不想分配 name inside case，不如赋值给case的结果。

Ruby 惯用版本：

beatles.each do |beatle|
  beatle[:name] =
    case beatle[:nickname]
    when "The Smart One" then "John"
    when "The Funny One" then "Ringo"
    when "The Cute One" then "Paul"
    when "The Quiet One" then "George"
    end
end

如何使用 case 语句遍历对象数组并将值添加到数组内的键？

How do I use a case statement to loop through an array of objects and add a value to a key inside the array?

ruby

case-statement