将驼峰案例转换为ruby中的下划线案例

Question

是否有任何现成的函数将驼峰案例字符串转换为下划线分隔字符串？

我想要这样的东西:

"CamelCaseString".to_underscore      

返回"camel_case_string".

...

Answer 1

Rails的ActiveSupport 使用以下内容为String添加下划线:

class String
  def underscore
    self.gsub(/::/, '/').
    gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
    gsub(/([a-z\d])([A-Z])/,'\1_\2').
    tr("-", "_").
    downcase
  end
end

然后你可以做有趣的事情:

"CamelCase".underscore
=> "camel_case"

Answer 2

您可以使用

"CamelCasedName".tableize.singularize

要不就

"CamelCasedName".underscore

两种选择方式都会产生"camel_cased_name".您可以在此处查看更多详细信息.

Answer 3

单行Ruby实现:

class String
   # ruby mutation methods have the expectation to return self if a mutation occurred, nil otherwise. (see http://www.ruby-doc.org/core-1.9.3/String.html#method-i-gsub-21)
   def to_underscore!
     gsub!(/(.)([A-Z])/,'\1_\2')
     downcase!
   end

   def to_underscore
     dup.tap { |s| s.to_underscore! }
   end
end

所以 "SomeCamelCase".to_underscore # =>"some_camel_case"

Answer 4

有一个称为"下划线"的Rails内置方法,您可以将其用于此目的

"CamelCaseString".underscore #=> "camel_case_string" 

'下划线'方法通常可以被视为'camelize'的倒数

Answer 5

以下是Rails的用法:

   def underscore(camel_cased_word)
     camel_cased_word.to_s.gsub(/::/, '/').
       gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
       gsub(/([a-z\d])([A-Z])/,'\1_\2').
       tr("-", "_").
       downcase
   end

Answer 6

如果有人在寻找需要将下划线应用于带空格的字符串并希望将它们转换为下划线的情况下，您可以使用这样的东西

'your String will be converted To underscore'.parameterize.underscore
#your_string_will_be_converted_to_underscore

或者只使用 .parameterize('_') 但请记住，不推荐使用这个

'your String will be converted To underscore'.parameterize('_')
#your_string_will_be_converted_to_underscore

Answer 7

接收器转换为蛇案:http://rubydoc.info/gems/extlib/0.9.15/String#snake_case-instance_method

这是DataMapper和Merb的支持库.(http://rubygems.org/gems/extlib)

def snake_case
  return downcase if match(/\A[A-Z]+\z/)
  gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2').
  gsub(/([a-z])([A-Z])/, '\1_\2').
  downcase
end

"FooBar".snake_case           #=> "foo_bar"
"HeadlineCNNNews".snake_case  #=> "headline_cnn_news"
"CNN".snake_case              #=> "cnn"

Answer 8

从Ruby Facets查看snakecase

处理以下案例,如下所示:

"SnakeCase".snakecase         #=> "snake_case"
"Snake-Case".snakecase        #=> "snake_case"
"Snake Case".snakecase        #=> "snake_case"
"Snake  -  Case".snakecase    #=> "snake_case"

来自:https://github.com/rubyworks/facets/blob/master/lib/core/facets/string/snakecase.rb

class String

  # Underscore a string such that camelcase, dashes and spaces are
  # replaced by underscores. This is the reverse of {#camelcase},
  # albeit not an exact inverse.
  #
  #   "SnakeCase".snakecase         #=> "snake_case"
  #   "Snake-Case".snakecase        #=> "snake_case"
  #   "Snake Case".snakecase        #=> "snake_case"
  #   "Snake  -  Case".snakecase    #=> "snake_case"
  #
  # Note, this method no longer converts `::` to `/`, in that case
  # use the {#pathize} method instead.

  def snakecase
    #gsub(/::/, '/').
    gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
    gsub(/([a-z\d])([A-Z])/,'\1_\2').
    tr('-', '_').
    gsub(/\s/, '_').
    gsub(/__+/, '_').
    downcase
  end

  #
  alias_method :underscore, :snakecase

  # TODO: Add *separators to #snakecase, like camelcase.

end

Answer 9

当你还包含空格时,CamelCases的短连接器(如果你的中间有一个带有小字母的单词,则无法正常工作):

a = "Test String"
a.gsub(' ', '').underscore

  => "test_string"