Question

I need a generic way to convert classnames to lowercase with underscores. For example, I wish to convert the classname NewUserBatch to new_user_batch. How to do this?

Answer 1

In the simple case, where you only have non-namespaced class names, you can use this oneliner:

EDIT: updated with positive look-ahead assertion (thanks @vladr)

"MYRubyClassName".gsub(/(.)([A-Z](?=[a-z]))/,'\1_\2').downcase

# => "my_ruby_class_name"

This finds all uppercase chars that follow another char and in turn is followed by a lower case char, inserts underscore before it and then downcases everything.