如何替换字符串中匹配的字符？（红宝石）

我正在构建一个刽子手游戏，我不知道如何用 player_input (Array) 中的匹配字母替换 hidden_​​word (String) 中的下划线。任何想法我应该做什么？提前谢谢你，我很感激！

def update
  if @the_word.chars.any? do |letter|
     @player_input.include?(letter.downcase)
     end
     puts "updated hidden word" #how to replace underscores?
  end
  puts @hidden_word
  puts "You have #{@attempts_left-1} attempts left."
end

我有两个字符串，the_word 和 hidden_​​word，还有一个数组，player_input。每当玩家选择与 the_word 匹配的字母时，hidden_​​word 应该更新。

例如

the_word = "红宝石"

hidden_​​word = "_ _ _ _"

玩家选择“g”，hidden_​​word 仍然是“_ _ _ _”

玩家选择“r”，hidden_​​word 更新“R _ _ _”

下面是代码的其余部分：

class Game
    attr_reader :the_word

    def initialize
        @the_word = random_word.upcase
        @player_input = Array.new
        @attempts_left = 10
    end

    def random_word
        @the_word = File.readlines("../5desk.txt").sample.strip()
    end

    def hide_the_word
        @hidden_word = "_" * @the_word.size
        puts "Can you find out this word? #{@hidden_word}"
        puts "You have #{@attempts_left} attempts left."
        puts @the_word #delete this
    end

    def update
        if @the_word.chars.any? do |letter|
            @player_input.include?(letter.downcase)
            end
            puts "updated hidden word" #how to replace underscores?
        end
        puts @hidden_word
        puts "You have #{@attempts_left-1} attempts left."
    end

    def guess_a_letter
        @player_input << gets.chomp
        puts "All the letters you have guessed: #{@player_input}"
    end

    def has_won?
        if !@hidden_word.include?("_") || @player_input.include?(@the_word.downcase)
            puts "You won!"
        elsif @attempts_left == 0
            puts "You lost..."
        end
    end

    def game_round #the loop need fixin
        puts "Let's play hangman!"
        hide_the_word
        while @attempts_left > 0
            guess_a_letter
            update
            @attempts_left -= 1 #fix this
            has_won?
            break if @player_input.include?("q") #delete this
        end
    end
end


new_game = Game.new
new_game.game_round