rails 仅显示视图中的前 50 个字符字段

rails Display only the first 50 characters field in view

只显示前 50 个字符 <%= news.header %>
查看:

<% @news.each do |news| %>
          <div class="news">
      <div class="title"> <%= news.title %> </div>
    <div class="photo"><%= image_tag( "1.jpg", :width =>247, :crop => :fit) %> </div>
      <div class="header"> <%= news.header %></div>
          <div class="cl"></div>
             </div>
    <% end %>

控制器:

def index
@news=News.all
end
<%= news.header.truncate(50) %>

http://api.rubyonrails.org/v4.2.7/classes/String.html#method-i-truncate