Craft 3 version - How to get entries related to current category only (not children)

Question

I need some help with syntax on this for Craft 3, please.

I want to use this piece of code:

{% set fruitEntries =  craft.entries.relatedTo({ relatedTo: catP,id: 'and, not '~str }) %}

from this answer here:

How to get entries related to current category only (not children)

It's exactly what I need to do but I'm not sure how to code it for Craft 3 so that I can pull in entries from JUST my 'products' section:

craft.entries.section('products')...

Thanks in advance.

---

UPDATED INFO.

Category Group = Products

Entry Sections using these categories = Products & Case Studies

My category structure is as follows:

Categories are:

• Travelling Irrigators
  • Superseeded Models
• Hydrants
• Filters
• Pontoons
• Pumps

I'm trying to return just the product entries (not case studies) under 'Travelling Irrigators' but not including the 'Superseeded Models'.

The other post does exactly what I need but it returns the case studies too.

Answer 1

These two pages should help you from the Craft 3 docs

https://docs.craftcms.com/v3/dev/element-queries/entry-queries.html#relatedto

https://docs.craftcms.com/v3/relations.html

Answer 2

So I finally got there in the end and am posting in case it helps anyone else.

I was building a drop down menu with bootstrap that showed a 2 tier category / entry menu.

Code as follows:

<ul class="dropdown-menu" aria-labelledby="navbarDropdown">

{% set catsL1 = craft.categories().group('products').level(1).all() %}    
{% for cat in catsL1 %} 

    {% set childCats = craft.categories.descendantOf(cat) %}
    {% set catParent = craft.categories.id(cat).one() %}
    {% set dontInclude = [] %}
    {% for child in craft.categories.descendantOf(cat).all() %}
        {% set dontInclude = dontInclude|merge(craft.entries.section('products').relatedTo(child).ids) %}
    {% endfor %}
    {% set str = dontInclude|join(', not ') %}
    {% set hideEntries = craft.entries({ relatedTo: cat,id: 'and, not '~str }) %}

        {% if hideEntries|length %}

        <!-- if we have some entries in the parent category, output them in a dropdown menu -->
        <li class="dropdown-submenu dropdown">
            <a class="dropdown-item dropdown-toggle" href="#" id="navbarSubDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">{{ cat.title }}</a>
            <ul class="dropdown-menu" aria-labelledby="navbarSubDropdown">
                {% for ent in hideEntries.section('products').all() %}
                <li><a href="{{ cat.url }}/{{ ent.slug }}" class="dropdown-item" style="color:grey">{{ ent.title }}</a></li>
                {% endfor %}

                <!-- check to see if sub categories exist -->
                {% if childCats|length %}
                    {% for subCat in childCats.all() %}

                        <!-- check to see if there are entries within the sub categories -->
                        {% set subEntries = craft.entries.section('products').relatedTo(subCat).all() %}
                        {% if subEntries|length %}
                        <li class="dropdown-submenu dropdown">
                            <a class="dropdown-item dropdown-toggle" href="#" id="navbarSubDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">{{ subCat.title }}</a>
                            <ul class="dropdown-menu" aria-labelledby="navbarSubDropdown">
                                {% for entry in subEntries %}
                                    <li><a href="{{ cat.url }}/{{ subCat.slug }}/{{ entry.slug }}" class="dropdown-item">{{ entry.title }}</a></li>
                                {% endfor %}
                            </ul>
                        </li>
                        {% else %}
                        <!-- if no entries then just output the child categories -->
                        <li><a href="{{ subCat.url }}" class="dropdown-item">{{ entry.title }}</a></li>
                        {% endif %}


                    </li>
                    {% endfor %}
                {% endif %}
            </ul>
        </li>

        {% else %}

            <!-- check to see if there are sub category entries, if so, output them in a dropdown -->
            {% set subEntries = craft.entries.section('products').relatedTo(cat).all() %}
            {% if subEntries|length %}
            <li class="dropdown-submenu dropdown">
                <a class="dropdown-item dropdown-toggle" href="#" id="navbarSubDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">{{ cat.title }}</a>
                <ul class="dropdown-menu" aria-labelledby="navbarSubDropdown">
                    {% for entry in subEntries %}
                        <li><a href="{{ cat.url }}/{{ entry.slug }}" class="dropdown-item">{{ entry.title }}</a></li>
                    {% endfor %}
                </ul>
            </li>
            {% else %}
            <!-- if no entries, then just show the top level categories -->
            <li><a href="{{ cat.url }}" class="dropdown-item">{{ cat.title }}</a></li>
            {% endif %}

        {% endif %}

    </li>

{% endfor %}

</ul>