class Array

  unless method_defined?(:select!)

    # As with #select but modifies the Array in place.
    #
    #   a = [1,2,3,4,5,6,7,8,9,10]
    #   a.select!{ |e| e % 2 == 0 }
    #   a  #=> [2,4,6,8,10]
    #
    # CREDIT: Gavin Sinclair
    #
    def select!  # :yield:
      reject!{ |e| not yield(e) }
    end

  end

end