ruby - 我将整数更改为字符串，但#gsub 只能识别 0-9

Question

我正在自学 Ruby，其中一项作业是生成凯撒密码。 使用#gsub，我已经能够将我的字母更改为整数 ('c' => 2)，移动它们，然后将新整数更改为字符串 (2 => "2")。

我碰壁了，Ruby 文档没有帮助。当我尝试将字符串 #gsub 变回字母 ("2"=> 'c') 时，它只能识别 0-9。之后的所有内容只是这些数字的串联(“12”=>“bc”而不是 =>“l”)。

为什么 Ruby 会这样，我该如何解决？

感谢您的帮助。

代码:(我知道这是草率的初学者代码；通过后我会尝试编辑它)

def convert_to_integer
    puts "What would you like to encode?"
    words = gets.chomp

    words = words.split("")
    words.map { |words| words.gsub!(/[a-z]/, 'a' => 0, 'b' => 1, 'c' => 2, 'd' => 3, 'e' => 4, 'f' => 5, 'g' => 6, 'h' => 7, 'i' => 8, 'j' => 9, 'k' => 10, 'l' => 11, 'm' => 12, 'n' => 13, 'o' => 14, 'p' => 15, 'q' => 16, 'r' => 17, 's' => 18, 't' => 19, 'u' => 20, 'v' => 21, 'w' => 22, 'x' => 23, 'y' => 24, 'z' => 25)
    }
    integer = words.map! { |letter| letter.to_i }

    return integer
end

def shift_left(integer, number = 0)
    puts "How many letters (to the left) would you like to shift it?"
    number = gets.to_i

    integer.map! { |n| n - number }

    return integer
end

def convert_to_letter(integer)
    integer.map! { |integer| integer.to_s }

    integer.map! { |n| n.gsub(/[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 , 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25]/, '0' => 'a', '1' => 'b', '2' => 'c', '3' => 'd', '4' => 'e', '5' => 'f', '6' => 'g', '7' => 'h', '8' => 'i', '9' => 'j', '10' => 'k', '11' => 'l', '12' => 'm', '13' => 'n', '14' => 'o', '15' => 'p', '16' => 'q', '17' => 'r', '18' => 's', '19' => 't', '20' => 'u', '21' => 'v', '22' => 'w', '23' => 'x', '24' => 'y', '25' => 'z')
    }
    print integer
end
convert_to_letter(shift_left(convert_to_integer))    

Answer 1

你不需要在那里做一个gsub。 gsub 通常用于替换较大字符串的部分。你想更换整个东西。

这应该可以解决问题:

def convert_to_letter(integers)
  replacements = {0 => 'a', 1 => 'b', 2 => 'c', 3 => 'd', 4 => 'e', 
    5 => 'f', 6 => 'g', 7 => 'h', 8 => 'i', 9 => 'j', 10 => 'k', 
    11 => 'l', 12 => 'm', 13 => 'n', 14 => 'o', 15 => 'p', 16 => 'q', 
    17 => 'r', 18 => 's', 19 => 't', 20 => 'u', 21 => 'v', 22 => 'w', 
    23 => 'x', 24 => 'y', 25 => 'z'  
  }

  integers.map{|x| replacements[x]}.join
end

另外，要小心破坏性操作(此处为 map!)。您可能会遇到意外的副作用(例如，某些数组会在您认为不应该更改时更改)。