Jekyll show post count for sub categories

Question

I have a Jekyll site built and for the posts, I have 3 sub-categories.

These categories are: blog examples tips

In each one of these categories I also have sub-categories for html, css and js.

In each post I have front-matter and a categories tag which looks like this as an example:

---

categories: - blog

- html

I would like to create a loop that outputs the post count for each category. So if under blogs I have 2 posts in each sub-category:

• blogs
  • HTML
  • html-post1.md
  • html-post2.md
  • css
  • css-post1.md
  • css-post2.md
  • js
  • js-post1.md
  • js-post2.md

How can I loop over this to just display the count instead of outputting each post?

Answer 1

You can loop directly over your site's categories like this:

<ul>
{% for cat in site.categories %}
    <li>{{ cat[0] }} ({{ cat[1].size }})</li>
{% endfor %}
</ul>

cat[0] is the category's name.
cat[1] is an array of all posts with that category, so cat[1].size is the number of posts.

The resulting HTML will look like this:

<ul>
    <li>HTML (2)</li>
    <li>css (2)</li>
    <li>js (2)</li>
</ul>

Note that the list of categories is unordered by default.
If you want to order it by name or post count, the solution is slightly more complicated.

Answer 2

For each category you could include a count like this:

  {% assign total = 0 %}
  {% for post in site.posts %}
     {% if post.category == "some_category" %}
      {% assign total = total | plus: 1 %}
     {% endif %}
  {% endfor %}