字符串 驼峰 蛇形

驼峰 转 蛇形

CamelCase.camelize

蛇形 转 驼峰

1. Rails的的ActiveSupport 加上下划线为以下几点：

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

那么你可以做有趣的东西：

"CamelCase".underscore

2.
一个班轮ruby

class String
 # ruby mutation methods have the expectation to return self if a mutation occurred, nil otherwise. (see  CodeGo.net
 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"

3.
下面是Rails如何做的：

 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

4.
接收器转换成蛇的情况下：
这是DataMapper的和Merb的支持库。 （

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"