How can I create a loop to cycle thru each category and the the entries within each category?

Question

So, I have a loop that populates all the entries related to a given category. See below. I have multiple categories. Right now, I use the same code for each category - swapping only the name of the category out (e.g, category1, category2 ...). How can I build a loop that avoids this?

My current template is as follows. I did not include the repetition for each category.

    <div class="margin-2"></div>
        {% set category = craft.entries.seciont('posts') %}


        <h6>Aircraft</h6>
        <div class="sep red margin-1"></div>
        <div class="owl-carousel owl-thumbs">
            {% for entry in category.relatedTo(craft.categories.slug('category1')) %}
            <div class="thumb dark-overlay">
                <div class="photo">
                    <a href="{{entry.url}}">
                        <img src="{{ entry.postImage.first().getURL('thumbImage')}}" alt="" width="235" height="235">
                        <span class="info"><span class="big-excerpt"> {{ entry.title }} k</span></span>
                    </a>
                </div>
            </div>
            {% endfor %}

Answer 1

First you loop through the categories then use the category to loop through all the entries related to that category.

{% for category in craft.categories.group('categoryGroup') %}
  {% for post in craft.entries.section('posts').relatedTo(category) %}
    {# your markup #}
  {% endfor %}
{% endfor %}