Twig compare two values in different arrays - symfony

Question

First of all I'm learning Twig.
I was wondering if it is possible wit Twig to compare two different values from different arrays/lists?!
I have two list of items I call them like so:
{% if page.cart %}
{% for product in page.cart.products %}
{{ product.id }}
{% endfor %}
{% endif %}
And:
{% if products %}
{% for product in products %}
{{ product.id }}
{% endfor %}
{% endif %}
I want to compare both product.id's so I can create a new statement. Is there any way to compare both values? The idea is to check if an id is present in page.cart.products and if so then do something.
I want to create a new statement to display some info. Something like so:
{% if page.cart %}
{% for product in page.cart.products %}
{% set cartId %}{{ product.id }}{% endset %}
{% endfor %}
{% endif %}
{% if products %}
{% for product in products %}
{% set listId %}{{ product.id }}{% endset %}
{% endfor %}
{% endif %}
{% if cartId == listId %}
.... do this ....
{% endif %}
Any help greatly appreciated!

Answer 1

You can loop over one array and check if the id is present in the second one. If it's there, you can do something.
{# In case you want to store them, you can do so in an array #}
{% set repeatedIds = [] %}
{% for productCart in page.cart.products if page.cart %}
{% for product in products if products %}
{% if productCart.id == product.id %}
<p>This id -> {{ product.id }} is already in page.cart.products</p>
{% set repeatedIds = repeatedIds|merge([product.id]) %}
{% endif %}
{% endfor %}
{% endfor %}
{{ dump(repeatedIds) }}
It's a very basic search algorithm and the cost is quadratic. Obviously, there are more efficient ways to look for an element in an array (though more complicated to implement).
If the amount of products you have to deal with is not very big, you could use this solution. However, if you have, let's say, more than one hundred products in each array (or you feel that the algorithm is slowing down your loading time), you could do this process in the controller using more sophisticated methods and PHP and just pass the result to the template.
Hope it helps.