Question

我在Float类中编写了一个方法，它接受一个float（秒）并将其转换为倒数计时器。当我这样编写代码时，代码工作正常：

class Float
  def to_countdown
    (self % 60) == 1 ? cd_sec = "#{(self % 60).to_i} second" : ( (self % 60).to_i == 0 ? cd_sec = "" : cd_sec = "#{(self % 60).to_i} seconds" )
    ((self/60) % 60) == 1 ? cd_min = "#{((self/60) % 60).to_i} minute" : ( ((self/60) % 60).to_i == 0 ? cd_min = "" : cd_min = "#{((self/60) % 60).to_i} minutes" )
    (self/3600) == 1 ? cd_hour = "#{(self/3600).to_i} hour" : ( (self/3600).to_i == 0 ? cd_hour = "" : cd_hour = "#{(self/3600).to_i} hours" )
    (self/(60*60*24)) == 1 ? cd_day = "#{(self/(60*60*24)).to_i} day" : ( (self/(60*60*24)).to_i == 0 ? cd_day = "" : cd_day = "#{(self/(60*60*24)).to_i} days" )
    countdown = [cd_day, cd_hour, cd_min, cd_sec].reject! {|c| c == nil}
    return countdown.to_sentence
  end
end

509330.546146.to_countdown => "x days, y hours, z minutes, and a seconds"

我想重构它。我的最终结果是：

class Float
  def to_countdown
    s,m,h,d = (self % 60),((self/60) % 60),((self/3600)%24),(self/(60*60*24))
    s == 1 ? cd_sec  = "#{s.to_i} second" : ( s.to_i == 0 ? cd_sec  = "" : cd_sec  = "#{s.to_i} seconds" )
    m == 1 ? cd_min  = "#{m.to_i} minute" : ( m.to_i == 0 ? cd_min  = "" : cd_min  = "#{m.to_i} minutes" )
    h == 1 ? cd_hour = "#{h.to_i} hour"   : ( h.to_i == 0 ? cd_hour = "" : cd_hour = "#{h.to_i} hours" )
    d == 1 ? cd_day  = "#{d.to_i} day"    : ( d.to_i == 0 ? cd_day  = "" : cd_day  = "#{d.to_i} days" )
    countdown = [cd_day, cd_hour, cd_min, cd_sec].reject! {|c| c == nil}
    return countdown.to_sentence
  end
end

当我尝试重构版本时，我得到：

509330.546146.to_countdown => **undefined method `to_sentence' for nil:NilClass>.**

表示countdown为nil。我在重构版本中做错了什么？

Answer 1

替换此

countdown = [cd_day, cd_hour, cd_min, cd_sec].reject! {|c| c == nil}

用这个

countdown = [cd_day, cd_hour, cd_min, cd_sec].compact

另外，你正在使用爆炸版。它就地改变了数组can return nil。如果您想继续使用reject，请使用常规版本（非爆炸性）。

为什么这个重构的ruby方法返回nil？

1 个答案: