循环条件的液体数组？

Question

我有一系列帖子，每个帖子都有一个类别。我想显示这些类别子集的 3 篇帖子(我们会说 a、b、c)。有什么方法可以用核心液体来做到这一点吗？除非我只是没有想到一些我认为不存在的事情。

帖子示例数组:

[
 {title: post 1, category: {id: a}},
 {title: post 2, category: {id: b}},
 {title: post 3, category: {id: c}},
 {title: post 4, category: {id: d}},
 {title: post 5, category: {id: b}}
]

我需要类似这样的伪代码:

{% for post in posts where category.id == a|b|c limit: 3 %}

或

{% for post in posts %}
  {% if post.category.id == a|b|c limit: 3 %}

Answer 1

这里有一个方法:

{% assign counter = 0 %}
{% for post in posts %}
  {% if counter < max and categories contains post.category.id %}
    {% assign counter = counter | plus:1 %}
    counter={{counter}}, post= {{post.title}} 
  {% endif %}
{% endfor %}

运行以下 Ruby 脚本:

#!/usr/bin/env ruby
require 'liquid.rb'

template = <<BLOCK
{% assign counter = 0 %}
{% for post in posts %}
  {% if counter < max and categories contains post.category.id %}
    {% assign counter = counter | plus:1 %}
    counter={{counter}}, post= {{post.title}} 
  {% endif %}
{% endfor %}
BLOCK

posts = [
  { "title" => "post 1", "category" => { "id" => "a" } },
  { "title" => "post 2", "category" => { "id" => "e" } },
  { "title" => "post 3", "category" => { "id" => "c" } },
  { "title" => "post 4", "category" => { "id" => "d" } },
  { "title" => "post 5", "category" => { "id" => "f" } },
  { "title" => "post 6", "category" => { "id" => "b" } },
  { "title" => "post 7", "category" => { "id" => "e" } },
  { "title" => "post 8", "category" => { "id" => "b" } }
]

print Liquid::Template.parse(template).render({
    'posts' => posts, 
    'max' => 3,
    'categories' => ['a', 'b', 'c']
})

产生以下输出:

counter=1, post= post 1    
counter=2, post= post 3 
counter=3, post= post 6 

(不过删除了一些换行符)