一行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"

我有麻烦运行“CamelCaseString”。在rake任务中使用下划线。这帮助了我:

ActiveSupport::Inflector.underscore "CamelCaseString"
=> "camel_case_string"

当然，您需要使用ActiveSupport

一行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"

我想要这样:

class String

  # \n returns the capture group of "n" index
  def snakize
    self.gsub(/::/, '/')
    .gsub(/([a-z\d])([A-Z])/, "\1_\2")
    .downcase
  end

  # or

  def snakize
    self.gsub(/::/, '/')
    .gsub(/([a-z\d])([A-Z])/) do
      "#{$1}_#{$2}"
    end
    .downcase
  end

end

猴子补丁的字符串类。有些类以两个或多个大写字母开头。

ruby内核本身不支持将字符串从(上)驼峰格式转换为(也称为pascal格式)下划线格式(也称为蛇形格式)。

因此，您需要创建自己的实现，或者使用现有的gem。

有一个叫做lucky_case的小红宝石宝石，它允许你将一个字符串从任何一个支持的10+ case轻松转换为另一个case:

require 'lucky_case'

# convert to snake case string
LuckyCase.snake_case('CamelCaseString')      # => 'camel_case_string'
# or the opposite way
LuckyCase.pascal_case('camel_case_string')   # => 'CamelCaseString'

如果你想，你甚至可以猴子修补String类:

require 'lucky_case/string'

'CamelCaseString'.snake_case  # => 'camel_case_string'
'CamelCaseString'.snake_case! # => 'camel_case_string' and overwriting original

请查看官方存储库以获得更多示例和文档:

https://github.com/magynhard/lucky_case

下面是Rails是如何做到的:

   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