动态变量值

Question

我正在寻找一些关于动态变量的建议。特别是如果我充分利用instance_variable_set或者我应该看到更好的方法。提前感谢您的任何建议。现在代码。

我正在创建一个二十一点游戏。我有两个value_creator方法看起来像这样：

class Blackjack 

    def dealers_card_value_creator 
    @card_value = @hit_dealer 
     case 
     when @card_value.match(/\d+/) 
     @card_value = @card_value.match(/\d+/)[0].to_i 
     when @card_value.match(/Ace/) 
     if @dealers_hand >= 11 
      @card_value = 1 
     else 
      @card_value = 11 
     end 
     when @card_value.match(/Jack|Queen|King/) 
     @card_value = 10 
     else 
     puts "there was an error. please try again." 
     end 
    @hit_dealer = @card_value 
    @dealers_hand = @dealers_hand + @hit_dealer 
     if @dealers_hand > 21 then puts "Dealer went over 21. You won $#{@bet}. Nice!" 
     deal end 
    end 

def players_card_value_creator 
    @card_value = @hit_player 
    case 
    when @card_value.match(/\d+/) 
     @card_value = @card_value.match(/\d+/)[0].to_i 
    when @card_value.match(/Ace/) 
     if @players_hand >= 11 
     @card_value = 1 
     else 
     @card_value = 11 
     end 
    when @card_value.match(/Jack|Queen|King/) 
     @card_value = 10 
    else 
     puts "there was an error. please try again." 
    end 
    @hit_player = @card_value 
    @players_hand = @players_hand + @hit_player 
     if @players_hand > 21 then puts "You went over 21. You lost $#{@bet}. Try again." 
     deal end 
    end 
end 

你可以看到，他们基本上是相同的。所以我创建了这个方法供经销商和玩家使用。

def value_creator(string) 
    hit = "@#{string}" #returns either @player or @dealer 
    instance_variable_set(hit, "#{@hit_card}") 
    @card_value = hit 
    case 
    when @card_value.match(/\d+/) 
     @card_value = @card_value.match(/\d+/)[0].to_i 
    when @card_value.match(/Ace/) 
     if "@#{string}"_hand >= 11 
     @card_value = 1 
     else 
     @card_value = 11 
     end 
    when @card_value.match(/Jack/) 
     @card_value = 10 
    when @card_value.match(/Queen/) 
     @card_value = 10 
    when @card_value.match(/King/) 
     @card_value = 10 
    else 
     puts "there was an error. please try again." 
    end 
    "@#{string}" = @card_value 
    "@#{string}"_hand = "@#{string}"_hand + "@#{string}" 
    end 

    def hit_dealer 
    @hit_card = @shuffled_deck.pop 
    value_creator("dealer") 
    end 

    def hit_player 
    @hit_card = @shuffled_deck.pop 
    value_creator("player") 
    end 

但是当我尝试调用"@#{string}"值与hit_player返回@player，没有被分配的值。

很多代码，但我希望它有助于更​​好地理解我正在尝试做什么，并将有助于更好地指导建议。再次，在此先感谢。

Answer 1

在

hit = "@#{string}" #returns either @player or @dealer 

的评论是不正确的。 结果不是@player或@dealer，它是字符串'@player'或'@dealer'。

你可以这样做：

def value_creator(variant) 
    case variant 
    when :player 
     hit = @player 
    when :dealer 
     hit = @dealer 
    else 
     raise ArgumentError 
    end 
    #.... 
end 
def hit_dealer 
    @hit_card = @shuffled_deck.pop 
    value_creator(:dealer) 
end 

def hit_player 
    @hit_card = @shuffled_deck.pop 
    value_creator(:player) 
end 

另一种方法：instance_variable_get来获取值。其他

hit = instance_variable_get("@#{string}") 

两种可能性：

hit = eval("@#{string}") 

（我不喜欢它 - EVAL是邪恶的）。

并与send。

你必须定义两个访问第一：

attr_reader :player 
attr_reader :dealer 

然后你可以使用：

def value_creator(string) 
    hit = send(string)