gistfile1.rb

# Sort lexicographically, but sorting numbers into their proper position.
# Ruby 1.9 only as the zero-width lookbehind assertions require Oniguruma.
# 
class Array
  def sort_preserving_numbers
    sort_by { |x|
      x.split(%r{(?<=\D)(?=\d)|(?<=\d)(?=\D)}).
        map { |piece| (piece =~ /\A\d+\z/) ? piece.to_i : piece }
    }
  end
end

# USAGE:
array = (7..12).map{ |x| "I have #{x} apples" }
array.sort
# => ["I have 10 apples", "I have 11 apples", "I have 12 apples", "I have 7 apples", "I have 8 apples", "I have 9 apples"]

array.sort_preserving_numbers
# => ["I have 7 apples", "I have 8 apples", "I have 9 apples", "I have 10 apples", "I have 11 apples", "I have 12 apples"]