ruby - 从方法执行下一个

Question

这段代码:

def skip_if_three(count)
    puts 'three detected, let\'s skip this loop!' if count == 3
end

5.times do |count|
    skip_if_three(count)
    puts count
end

返回:

0
1
2
three detected, let's skip this loop!
3                                                           # don't want this to appear!
4

但是，如果使用下一个关键字并执行此操作:

def skip_if_three(count)
    next if count == 3
end

5.times do |count|
    skip_if_three(count)
    puts count
end

我得到这个语法错误:

Invalid next

这在意料之中。但是如何使用助手的 next 呢？

更新

我正在使用嵌套循环并且需要在每个循环中执行我的检查，所以我想保持它干燥，因此使用外部方法。

5.times do |i|
    skip_if_three(i)
    puts count

    5.times do |j|
         skip_if_three(j)
         puts count
    end
end

Answer 1

def skip_if_three(count)
  return unless count == 3
  puts "three detected, let's skip this loop!"
  throw(:three)
end

5.times do |count|
  catch(:three) do
    skip_if_three(count)
    puts count
  end
end

结果:

0
1
2
three detected, let's skip this loop!
4

---

def three?(count)
  return unless count == 3
  puts "three detected, let's skip this loop!"
  true
end

5.times do |count|
  puts count unless three?(count)
end

结果:

0
1
2
three detected, let's skip this loop!
4

---

def three?(count)
  return unless count == 3
  puts "three detected, let's skip this loop!"
  true
end

5.times do |count|
  next if three?(count)
  puts count
end

结果:

0
1
2
three detected, let's skip this loop!
4