version_sort, accounts for differences in the letter before .ext by converting it to the ASCII code first

version_sort.rb

require 'pry'

class Array
  def version_sort
    array = self.sort_by do |file|
      file.gsub(/[a-z].ext/) {|x| x.ord }
    end

    array.sort_by do |item|
      item.scan(/\d+|[a-z]*/).collect do |el|
        el.to_i
      end
    end
  end
end


filenames = [
  "foo-1.10.2.ext",
  "foo-1.11.ext",
  "foo-1.3.ext",
  "foo-1.50.ext",
  "foo-1.8.7.ext",
  "foo-1.9.3.ext",
  "foo-1.ext",
  "foo-10.1.ext",
  "foo-10.ext",
  "foo-100.ext",
  "foo-13.ext",
  "foo-2.0.0.ext",
  "foo-2.0.1.ext",
  "foo-2.0.ext",
  "foo-2.007.ext",
  "foo-2.01.ext",
  "foo-2.012b.ext",
  "foo-2.01a.ext",
  "foo-2.0b.ext",
  "foo-2.0a.ext",
  "foo-2.1.ext",
  "foo-25.ext",
  "foo-6.ext",
]
version_sorted_filenames = [
  "foo-1.ext",
  "foo-1.3.ext",
  "foo-1.8.7.ext",
  "foo-1.9.3.ext",
  "foo-1.10.2.ext",
  "foo-1.11.ext",
  "foo-1.50.ext",
  "foo-2.0.ext",
  "foo-2.0a.ext",
  "foo-2.0b.ext",
  "foo-2.0.0.ext",
  "foo-2.0.1.ext",
  "foo-2.01.ext",
  "foo-2.1.ext",
  "foo-2.01a.ext",
  "foo-2.007.ext",
  "foo-2.012b.ext",
  "foo-6.ext",
  "foo-10.ext",
  "foo-10.1.ext",
  "foo-13.ext",
  "foo-25.ext",
  "foo-100.ext",
]

# assert_equal filenames.version_sort, version_sorted_filenames
p (filenames.version_sort == version_sorted_filenames)
# puts (filenames.version_sort)
# puts filenames.sort_by {|word| word.length}

# binding.pry