Question

这几乎肯定是重复的，但我找不到原文 - 我不知道要使用的搜索条件。这就是我使用Stackoverflow而不是Google的原因：）

无论如何，这是我的代码：

def titleize(say)
  index = 0
  words = say.split
  words.each do |word|
    unless word == "and" || "or" || "over" || "the" || "for"
        word.capitalize!
    end
    if index == 0
        word.capitalize!
    end
    index += 1
  end
  say = words.join(" ")
end

因为索引是在循环之前声明的，所以if index == 0无效。我如何让Ruby知道并使用我的对象索引？还有：这叫什么？

Answer 1

使用index == 0完全没问题，因为索引可以在循环中访问。你真正的问题可能就在这一行：

word == "and" || "or" || "over" || "the" || "for"

这总是true - 就像！你的意思是：

["and", "or", "over", "the", "for"].include? word

除了表示有一个名为each_with_index的方法，您可以这样使用：

words.each_with_index do |word, index|

Answer 2

我认为你想使用with_index。你的单词比较也被破坏了。

def titleize(say)
  words = say.split
  l = ["and", "or", "over", "the", "for"]

  words.each.with_index do |word, index|
    word.capitalize! if index == 0 || !(l.include? word)
  end

  say = words.join(" ")
end

puts(titleize("hello there for you"))
puts(titleize("hi"))
puts(titleize("for"))

Answer 3

这不是布尔人的工作方式。评估方法是：

x == 'a' || 'b'

变为：

(x == 'a') || 'b'

相当于：

'b'

你想要的，翻译成更惯用的Ruby，是：

def titleize(say)
  say.split.each_with_index do |word, index|
    if (index == 0)
      word.capitalize!
    else
      case (word)
      when "a", "and", "or", "over", "the", "for"
        # Leave lower-case
      else
        word.capitalize!
      end
    end
  end.join(' ')
end

titleize('the time this is a test for the things!')
# => "The Time This Is a Test for the Things!"

Answer 4

我会这样做，它更灵活，更红宝石般的

def titleize(sentence,exclusions=[])
  sentence.split.map.with_index do |word,index|
    (index == 0 || !exclusions.include?(word)) ? word.capitalize : word
  end.join(' ')
end

对于这种情况，我使用了＆＃39;大写＆＃39;如果任何单词已经大写，则没有爆炸。

"Hello".capitalize! #=> nil
"Hello".capitalize #=> "Hello"

它还允许您重复使用相同的排除列表或根据需要更改它们

呼叫

exclude = ["and", "or", "over", "the", "for"]
titleize("hello there you are over there", exclude)
#=> "Hello There You Are over There"

Answer 5

您的代码返回say的修改，但确实会更改变量的内容。您似乎想要修改参数，但我不确定。我将首先建议一种方法来返回say的修改值（但不改变say的值，然后将显示如何更改代码以修改参数。

请注意，我没有使用索引，并使用case语句来确定第一个之后的单词是否应该大写。

<强>代码

def titleize(say)
  words = say.split
  return "" if words.empty?
  words.first.capitalize!
  return words.first if words.size == 1
  words[1..-1].each do |word|
    case word
    when "and", "or", "over", "the", "for"
    else
      word.capitalize!
    end
  end
  words.join(' ')
end

<强>实施例

say = "and now is the time for all Rubyists to hunker down and code"
titleize(say)
  #=> "And Now Is the Time for All Rubyists To Hunker Down and Code"
say
  #=> "and now is the time for all Rubyists to hunker down and code"    

say = "  "
titleize(say)
  #=> ""

say = " and "
titleize(say)
  #=> "And"

修改参数

如果您想修改参数say，请使用String#replace：

def titleize_and_modify_arg(say)
  words = say.split
  str =
  case words.size
  when 0
    ""
  when 1
    words.first.capitalize
  else
    words.first.capitalize!
    words[1..-1].each do |word|
      case word
      when "and", "or", "over", "the", "for"
      else
        word.capitalize!
      end
    end
    words.join(' ')
  end  
  say.replace(str)
end

say = "and now is the time for all Rubyists to hunker down and code"
titleize_and_modify_arg(say)
  #=> "And Now Is the Time for All Rubyists To Hunker Down and Code"
say
  #=> "And Now Is the Time for All Rubyists To Hunker Down and Code"

say = " and "
titleize_and_modify_arg(say)
  #=> nil
say
  #=> " and "

请注意，在第二个示例中，titleize_and_modify_arg正确修改了say，但返回nil。当然，如果需要，可以轻松更改方法以返回say的值，并更改它。

另请注意，在case语句中，words.siz => 1时，它是capitalize，而不是capitalize!，因为后者会返回nil如果这个词已经大写了。但是，capitalize!案件需要else。

Answer 6

我建议使用each_index代替each。请参阅here。

试试这个：

def titleize (say)
  words = say.split
  words.each_index do |index|
    word = words[i]
    unless word == "and" || "or" || "over" || "the" || "for"
        word.capitalize!
    end
    if index == 0
        word.capitalize!
    end
  end
  say = words.join(" ")
end

将值引入Ruby中的循环

6 个答案: