Ruby 的返回点是什么? [英] what is the point of return in Ruby?

问题描述

return 和只放一个变量有什么区别，比如下面:

What is the difference between return and just putting a variable such as the following:

def write_code(number_of_errors)
  if number_of_errors > 1
     mood = "Ask me later"
  else
     mood = "No Problem"
  end  
  mood
end

返回

def write_code(number_of_errors)
  if number_of_errors > 1
    mood =  "Ask me later"
  else
    mood = puts "No Problem"
  end  
  return mood
end

推荐答案

return 让你早点突破:

def write_code(number_of_errors)
  return "No problem" if number_of_errors == 0
  badness = compute_badness(number_of_errors)
  "WHAT?!  Badness = #{badness}."
end

如果number_of_errors == 0，则立即返回没问题".但是，正如您所观察到的，在方法的末尾是不必要的.

If number_of_errors == 0, then "No problem" will be returned immediately. At the end of a method, though, it's unnecessary, as you observed.

为了证明 return 立即退出，考虑这个函数:

To demonstrate that return exits immediately, consider this function:

def last_name(name)
  return nil unless name
  name.split(/\s+/)[-1]
end

如果你调用这个函数为last_name("Antal S-Z")，它会返回"S-Z".如果您将其称为 last_name(nil)，则返回 nil.如果return 没有立即中止，它会尝试执行nil.split(/\s+/)[-1]，这会抛出错误.

If you call this function as last_name("Antal S-Z"), it will return "S-Z". If you call it as last_name(nil), it returns nil. If return didn't abort immediately, it would try to execute nil.split(/\s+/)[-1], which would throw an error.

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