在Ruby中将空字符串转换为nil [英] Converting an empty string into nil in Ruby

问题描述

我有一个名为 word 的字符串和一个名为 infinitive 的函数，使得
word.infinitive 有时会返回另一个字符串，否则会返回一个空字符串
我正在尝试为

I have a string called word and a function called infinitive such that
word.infinitive would return another string on some occasions and an empty string otherwise
I am trying to find an elegant ruby one line expression for the code-snippet below

if word.infinitive == ""
      return word
else return word.infinitive

如果不定式返回nil而不是"，我可以做类似的事情

Had infinitive returned nil instead of "", I could have done something like

(word.infinitive or word)

但是由于没有，我无法利用短路OR
理想情况下，我想要
1)一个我可以轻松嵌入其他代码的表达式
2)不定式函数仅被调用一次
3)不要在我的代码中添加任何自定义的gem或插件

But since it does not, I can't take advantage of the short-circuit OR
Ideally I would want
1) a single expression that I could easily embed in other code
2) the function infinitive being called only once
3) to not add any custom gems or plugins into my code

推荐答案

如果您不因猴子修补和滥用语法而感到羞耻，则可以这样做:

If you're not ashamed of monkeypatching and abusing syntax, this would work:

class String
  def | x
    if empty? then x else self end
  end
end

然后您可以说 word.infinitive |单词，如果您问我，它实际上会自然扫描.

Then you can say word.infinitive | word, which actually scans fairly naturally, if you ask me.

但是，我认为一个更好的主意是修改不定式方法，或者添加一个不带单词的版本.

However, I think a better idea would be to modify the infinitive method, or add a version of it that returns the word unchanged.

这是一个可能更优雅的解决方案:

Here's a possibly more elegant solution:

[word.infinitive, word].find {|x| not x.empty?}

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