ruby 将内循环值返回给外循环

Question

如何将内部循环的值返回到外部循环的 .map，示例:

class LetterNumber
  def initialize(letter, number)
    @letter = letter
    @number = number
  end
end

do_stuff
  letter_numbers = // array of LetterNumber objects
  numbers = [1, 2, 3]

  letter_numbers.map do |letter_number|
    numbers.each do |number|
      letter_number.number = letter_number.number + number
    end
  end
end

我希望 do_stuff 方法返回更新后的 LetterNumber 对象的数组。所以我希望内循环在每次迭代时将一个 letter_number 对象返回给外循环。是否可以使用某种迭代器而不是将循环分解为单独的方法或其他东西？

Answer 1

可以使用inject方法直接计算和:

class LetterNumber
  def initialize(letter, number)
    @letter = letter
    @number = number
  end
end

def do_stuff
  letter_numbers = // array of LetterNumber objects
  numbers = [1, 2, 3]

  letter_numbers.map do |letter_number|
    letter.number += numbers.inject(:+)
    letter_number
  end
end

或使用 each_with_object 在循环后返回 letter_number。

def do_stuff
  letter_numbers = // array of LetterNumber objects
  numbers = [1, 2, 3]

  letter_numbers.map do |letter_number|
    numbers.each_with_object(letter_number) do |number|
      letter_number.number = letter_number.number + number
    end
  end
end