ruby - 如何将嵌套的字符数组连接到字符串

Question

我有以下代码:

def caesar_cipher(text, move_by)
    move_by %= 26
    chars = Hash[('a'..'z').map.with_index.to_a]
    converted = text.split.map do |word|
        word.chars.map do |char|
            if (chars[char.downcase] + move_by) <= 26
                chars.key(chars[char.downcase] + move_by)
            else
                chars.key(chars[char.downcase] + move_by - 26)
            end
        end
    end
end

print caesar_cipher("What a string", 5)

它将字符串从变量text转换为整数。这是运行时得到的输出: [["b", "m", "f", "y"], ["f"], ["x", "y", "w ", "n", "s", "l"]]，我希望它像这样“bmft f xywnsl” 那样连接。我尝试过 .join 方法，但它给了我 "bmftfxywnsl"

Answer 1

如果:

arr = [["b", "m", "f", "y"], ["f"], ["x", "y", "w", "n", "s", "l"]]

然后

arr.map(&:join).join(' ')
  #=> "bmfy f xywnsl" 

您可以将 map(&:join) 视为:

arr.map { |a| a.join }.join(' ')

Ruby 不是很棒吗？