monkey_patchy.rb

class Array
  def new_map
    new_array = []
    each do |item|
      new_array << yield(item)
    end
    new_array
  end

  def new_select!(&block)
    replace( select(&block) )
  end
end

class String
  def collapse
    split.join
  end

  def collapse!
    replace( collapse )
  end
end