group_by是一个很好的方法：

控制器：

  def archive 
 #this将返回一个哈希，其中月份名称是键
＃，值为属于这些月份的帖子的数组
 #something like：
＃{February=> [＃< Post 0xb5c836a0>，＃< Post 0xb5443a0>]，
＃'March'=> [＃< Post 0x43443a0>]} 
 @posts_by_month = Posts.find（：all）.group_by {| post | post.created_at.strftime（％B）} 
 end 
 

查看模板： / p>

 <％@ posts_by_month.each do | monthname，posts | ％GT; 
<％= monthname％> 
< ul> 
<％posts.each do | post | ％GT; 
< li><％= post.title％>< / li> 
<％end％> 
< / ul> 
<％end％> 
 

Hy guys. I've created a simple blog app with the usual CRUD actions. I've also added a new action in the PostController called "archive" and an associated view. In this view I want to bring back all blog posts and group them by month, displaying them in this kind of format:

March
<ul>
    <li>Hello World</li>
    <li>Blah blah</li>
    <li>Nothing to see here</li>
    <li>Test post...</li>
</ul>

Febuary
<ul>
    <li>My hangover sucks</li>
    ... etc ...

I can't for the life of me figure out the best way to do this. Assuming the Post model has the usual title, content, created_at etc fields, can someone help me out with the logic/code? I'm very new to RoR so please bear with me :)

group_by is a great method:

controller:

def archive
  #this will return a hash in which the month names are the keys, 
  #and the values are arrays of the posts belonging to such months
  #something like: 
  #{ "February" => [#<Post 0xb5c836a0>,#<Post 0xb5443a0>],
  # 'March' => [#<Post 0x43443a0>] }
  @posts_by_month = Posts.find(:all).group_by { |post| post.created_at.strftime("%B") }
end

view template:

<% @posts_by_month.each do |monthname, posts| %>
<%= monthname %>
<ul>
   <% posts.each do |post| %>
     <li><%= post.title %></li>
   <% end %>
</ul>
<% end %>