The reverse of camelize. Makes an underscored form from the expression in the string.

Changes ’::’ to ’/’ to convert namespaces to paths.

Examples

"ActiveRecord".underscore #=> "active_record"
"ActiveRecord::Errors".underscore #=> active_record/errors

Source Code

# File active_support/inflector.rb, line 175
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