twigfiddle.com - Fiddle l1qpzu v3 - Created on October 4, 2022 13:27

File

----
{% set combined_age = 0 %}
{% for person in people %}
    {%- if person.name is defined and person.name is not empty %}
        {{~ block('helloBlock', 'block.html.twig') ~}}
        {# combined age from the block cannot be passed back #}
        {% if person.dob is defined %}
            {% set year = person.dob|date('Y') %}
            {% set age = "now"|date('Y') - year %}
            {% set combined_age = combined_age + age %}
        {% endif %}
    {%- endif %}
{% endfor %}
----
Combined Age {{ combined_age }} years

File

{# The block definition can only reference variables defined until this point #}
{# When called the initial definition of person above will be overwritten #}
{% block helloBlock %}
    {% apply spaceless %}
        {% if person is not empty %}
            <div style="background-color:{{ person.color is defined ? person.color : 'inherit' }}">
                {% if person.name is defined %}
                    <h1>{{ person.name }}</h1>
                    <span class="greeting">Hello
                        {# should be better : having to do this so as not to escape tag as a variable #}
                        {% if person.url is defined and person.url is not empty %}
                            <a href="{{ person.url}}" target="_blank">{{ person.name }}</a>
                        {% else %}
                            {{ person.name }}
                        {% endif %}
                    </span>
                    {% if person.dob is defined %}
                        {% set year = person.dob|date("Y") %}
                        {% set age = "now"|date('Y') - year %}
                        <span class="dob">Date of Birth: {{ person.dob|date('d/m/Y') }}</span>
                        <span class="age">Age: {{ age }}</span>
                    {% endif %}
                    {% if person.likes is defined %}
                        {% for like in person.likes %}
                            {% if loop.last is not empty %}
                                <span class="like">{{ like }}</span>
                            {% endif %}
                        {% endfor %}
                    {% endif %}
                    {% if person.words is defined %}
                        {# filter out empty strings #}
                        {% set tempWords = [] %}
                        {% for word in person.words %}
                            {% if word is not empty %}
                                {% set tempWords = tempWords|merge([word]) %}
                            {% endif %}
                        {% endfor %}
                        {{ tempWords|join(", ", " and ") }}
                    {% endif %}
                {% endif %}
            </div>
        {% endif %}
    {% endapply %}
{% endblock %}

Format

{"people": [
    {
        "name": "James Readerbelly",
        "dob": "05/27/1972",
        "color" : "red",
        "url" : "https://www.bbc.co.uk",
        "words": ["1", "2", "3", "4"],
        "likes": ["Spending Money", "Sleeping", "Joshing"]
    },
    {
        "name": "Diane Readerdoer",
        "dob": "Apr 10th 1944",
        "color" : "yellow",
        "url" : "",
        "words": ["One", ""]
    },
    {
        "name": "Marcus Readermoaner",
        "dob": "September 12 1970",
        "words": ["One", "", "Three"]
    }
]}