invert

http://docs.ruby-lang.org/en/2.0.0/Hash.html

invert → new_hash
Returns a new hash created by using hsh's values as keys, and the keys as values.

h = { "n" => 100, "m" => 100, "y" => 300, "d" => 200, "a" => 0 }
h.invert   #=> {0=>"a", 100=>"m", 200=>"d", 300=>"y"}

 <td class="recommend"><%= subchannel_item.if_recommend %></td>

  RECOMMEND = {
    '否' => false,
    '是' => true
  }

  def if_recommend
    RECOMMEND.invert[recommend]
  end

[11] pry(main)> SubchannelItem::RECOMMEND
=> {"否"=>false, "是"=>true}
[12] pry(main)> SubchannelItem::RECOMMEND.invert
=> {false=>"否", true=>"是"}

[15] pry(main)> SubchannelItem::RECOMMEND.invert[SubchannelItem.first.recommend]
=> "是"