数组中根据某元素去重

def sub_search 
      @my_params=[['a','b','c'],['a','q','e'],['b','e','h']]
      check_params=[]
      @page_params=[]
      if @my_params.size>0
         @my_params.each do |x|
           unless check_params.include?(x[0])
             check_params<<x[0]
             @tag=1
           end
             @page_params<<x if @tag==1
             @tag=0
         end
      end
  end
 
  p @page_params  #=>[['a','b','c'],['b','e','h']]