# Advanced Filtering

URL: /docs/content/reuse/filtering/
Section: reuse
Tags: filtering, taxonomy, jinja

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Advanced Content Filtering Standard tag pages list content for one tag (e.g., /tags/python/). But sometimes users want to find content that matches multiple criteria, like &quot;Tutorials&quot; AND &quot;Python&quot; AND &quot;Beginner&quot;. This guide shows how to build an advanced filter using Jinja set logic. The Logic: Set Intersections Jinja allows us to treat lists of pages as mathematical sets. Union: All unique items in A or B. Intersection: Items that are in BOTH A and B. Difference: Items in A but not in B. Example: Building a &quot;Recipe Finder&quot; Imagine a documentation site where you want to find &quot;API Guides&quot; for &quot;v2.0&quot;. 1. Accessing the Data Bengal exposes site.taxonomies which gives us lists of pages for each tag. 1 2&#123;% set api_pages = site.taxonomies.tags[&quot;api&quot;].pages %&#125; &#123;% set v2_pages = site.taxonomies.tags[&quot;v2&quot;].pages %&#125; 2. Finding the Intersection We can find pages that exist in both lists. 1 2 3 4 5 6 7 8 9 10 11 12 13 14&#123;% set results = [] %&#125; &#123;% for page in api_pages %&#125; &#123;% if page in v2_pages %&#125; &#123;% do results.append(page) %&#125; &#123;% endif %&#125; &#123;% endfor %&#125; &lt;h2&gt;API v2 Guides ({{ results|length }})&lt;/h2&gt; &lt;ul&gt; &#123;% for page in results %&#125; &lt;li&gt;&lt;a href=&quot;{{ page.url }}&quot;&gt;{{ page.title }}&lt;/a&gt;&lt;/li&gt; &#123;% endfor %&#125; &lt;/ul&gt; Advanced: The &quot;Filter Page&quot; Layout For a dynamic filter page (e.g., /search/), we typically rely on client-side JavaScript because pre-rendering every combination of tags is expensive (combinatorial explosion). However, for specific, high-value combinations, you can create dedicated pages. Step 1: Create the Page site/content/guides/python-tutorials.md: 1 2 3 4 5 6--- title: Python Tutorials layout: filter_page filter_tags: [&quot;python&quot;, &quot;tutorial&quot;] --- Here are all our Python tutorials. Step 2: Create the Layout templates/filter_page.html: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31&#123;% extends &quot;base.html&quot; %&#125; &#123;% block content %&#125; &lt;h1&gt;{{ page.title }}&lt;/h1&gt; {# 1. Start with all site pages #} &#123;% set matches = site.pages %&#125; {# 2. Apply intersection for each required tag #} &#123;% for tag in page.filter_tags %&#125; &#123;% set tag_pages = site.taxonomies.tags[tag].pages %&#125; {# Use a custom filter or loop to intersect #} &#123;% set new_matches = [] %&#125; &#123;% for m in matches %&#125; &#123;% if m in tag_pages %&#125; &#123;% do new_matches.append(m) %&#125; &#123;% endif %&#125; &#123;% endfor %&#125; &#123;% set matches = new_matches %&#125; &#123;% endfor %&#125; {# 3. Render Results #} &lt;div class=&quot;results&quot;&gt; &#123;% for page in matches %&#125; &#123;% include &quot;partials/card.html&quot; %&#125; &#123;% else %&#125; &lt;p&gt;No matches found.&lt;/p&gt; &#123;% endfor %&#125; &lt;/div&gt; &#123;% endblock %&#125; Summary Use Set Intersections to build powerful &quot;Topic Pages&quot; that aggregate content from multiple dimensions without manually curating lists. Info Seealso Content Reuse — DRY content strategies Templating — Jinja2 fundamentals

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Metadata:
- Author: lbliii
- Word Count: 462
- Reading Time: 2 minutes