跳过直到特定数量的语句

Question

我有一种方法可以在墙上唱出“啤酒瓶”。我有一个问题，当它达到“1”时，我希望瓶子是单数而不是复数。

我设法通过创建一个“if”来做到这一点。当@bottles 达到1 这有效。但是，当 until 语句达到 1 时，它会说

'Take one down, pass one round
one bottles of beer'

此时我需要 until 语句来跳过它。这是怎么做到的？

'

 class BeerSong

  require 'humanize'

  attr_accessor :bottles

  def initialize(bottles)
  @bottles = bottles
  @bottles = 0 if @bottles < 0
  @bottles = 99 if @bottles > 99
  end

  public

  def print_song
  until @bottles == 0 do
   break if @bottles == 0
   puts "#{@bottles.humanize} bottles of beer on the wall"
   puts "#{@bottles.humanize} bottles of beer"
   puts "Take one down, pass one round"
   puts "#{(@bottles - 1).humanize} bottles of beer"
   @bottles = @bottles - 1
     if @bottles == 1
     puts "#{@bottle} bottle of beer on the wall"
     puts "#{@bottles.humanize} bottle of beer"
     puts "Take one down, pass one round"
     puts "#{(@bottles - 1).humanize} bottles of beer"
     @bottles = @bottles - 1
     end
    end
  end
end


beer = BeerSong.new(99)
beer.print_song

Answer 1

你需要做一个if/else，所以它只会在@bottles - 1 == 1时打印歌曲的单数形式，像这样：

def print_song
  until @bottles == 0 do
    puts "#{@bottles.humanize} bottles of beer on the wall"
    puts "#{@bottles.humanize} bottles of beer"
    puts "Take one down, pass one round"

    if @bottles - 1 == 1
      puts "#{(@bottles - 1).humanize} bottle of beer"
    else
      puts "#{(@bottles - 1).humanize} bottles of beer"
    end

    @bottles = @bottles - 1

    if @bottles == 1
      puts "#{@bottle} bottle of beer on the wall"
      puts "#{@bottles.humanize} bottle of beer"
      puts "Take one down, pass one round"
      puts "#{(@bottles - 1).humanize} bottles of beer"
      @bottles = @bottles - 1
    end
  end
end

虽然 plural 和 singular 不需要重复整首歌曲，但您可以使用变量并更改它（就像使用 @bottles ) 例如，当您到达1 时，print_song 可能是：

def print_song
  until @bottles == 0 do
    bottles = @bottles > 1 ? "bottles" : "bottle"
    puts "#{@bottles.humanize} #{bottles} of beer on the wall"
    puts "#{@bottles.humanize} #{bottles} of beer"
    puts "Take one down, pass one round"
    bottles = @bottles -1 == 1 ? "bottle" : "bottles"
    puts "#{(@bottles - 1).humanize}  #{bottles} of beer"
    @bottles -= 1
  end
end

注意这里使用了三元：

bottles = @bottles > 1 ? "bottles" : "bottle"

和做的一样：

if @bottles > 1
  bottles = "bottles"
else
  bottles = "bottle"
end

这里使用-=：

@bottles -= 1

和做的一样：

@bottles = @bottles - 1