split method name with regex and ruby

Question

I would like to use a regex to get every variant of a method name like this:

method_name = "my_special_title"
method_name_variants = ["my_special_title", "special_title", "title"]

I can do this with:

r = /((?:[^_]*_)?((?:[^_]*_)?(.*)))/
r.match("my_special_title").to_a.uniq
=> ["my_special_title", "special_title", "title"]

is it possible to have a arbitrary method length so we can have:

"my_very_special_specific_method" => ["my_very_special_specific_method", "very_special_specific_method", "special_specific_method", "specific_method", "method"]

Answer 1

Here's one way:

s = "my_very_special_specific_method"
a = s.split('_')
a.length.times.map { |n| a.from(n).join('_') }

=> ["my_very_special_specific_method", "very_special_specific_method", 
    "special_specific_method", "specific_method", "method"]