将字符串转换为标题大小写

Question

所以我是Ruby的新手，我的任务是手动将字符串转换为title-case。我终于能够创建一种我相信能够满足我的任务要求的方法(它不是很灵活，但它可以做到)，但是我遇到了最后一个障碍。我似乎不能将最后一个数组连接到一个字符串中。我的代码和Rspec错误如下。我认为我必须在某个地方使用.join(“")，但我不确定确切的语法。提前感谢您的帮助！

我的代码：

class Title
  attr_accessor :string

  def initialize(string)
    @string = string
  end

  def fix
    string.split(" ").each_with_index do |value, index|
      if index >= 2 && value.length <= 3
        value.downcase!
      else
        value.capitalize!
      end
    end
  end
end

Rspec：

expected: "The Great Gatsby"
     got: ["The", "Great", "Gatsby"]

(compared using ==)

exercise_spec.rb:6:in `block (3 levels) in <top (required)>'

再一次：

expected: "Little Red Riding Hood"
     got: ["Little", "Red", "Riding", "Hood"]

(compared using ==)

exercise_spec.rb:9:in `block (3 levels) in <top (required)>'

再一次：

expected: "The Lord of the Rings"
     got: ["The", "Lord", "of", "the", "Rings"]

(compared using ==)

exercise_spec.rb:12:in `block (3 levels) in <top (required)>'

再一次：

expected: "The Sword and the Stone"
     got: ["The", "Sword", "and", "the", "Stone"]

(compared using ==)

exercise_spec.rb:17:in `block (3 levels) in <top (required)>'

Answer 1

快速解决方案：

  def fix
    string.split(" ").each_with_index do |value, index|
      if index >= 2 && value.length <= 3
        value.downcase!
      else
        value.capitalize!
      end
      value
    end.join(" ")
  end

如果你想用红宝石的方式去做：

def fix
  string.split(" ").map(&:capitalize).join(" ")
end

Answer 2

ActiveSupport提供了一个名为titleize的方法，它可以完成您所描述的操作：

>> "the great gatsby".titleize
=> "The Great Gatsby"
>> "little red riding hood".titleize
=> "Little Red Riding Hood"
>> "the lord of the rings".titleize
=> "The Lord Of The Rings"

来源：http://apidock.com/rails/ActiveSupport/Inflector/titleize

Answer 3

要提供替代解决方案，请执行以下操作：

def fix
  string.downcase.gsub(/^\S+|(\S{4,})/, &:capitalize)
end

这只是将出现在字符串开头或长度为4+个字符的每个单词替换为其大写形式。