Output array in Twig

You can use join to output an array as a concatenated string. It behaves like implode() in php.

Example:

{{ [1, 2, 3]|join }}
{# returns 123 #}

{{ [1, 2, 3]|join('|') }}
{# outputs 1|2|3 #}

{{ [1, 2, 3]|join(', ', ' and ') }}
{# outputs 1, 2 and 3 #}

See the twig join documentation.


So, as error shows you are trying convert array (in category variable) to string. You can preview array by dump() (doc.). In your case:

{% for category in user.profile.category %}
    {{ dump(category) }}
{% endfor %}

Please notice that dump() should be use only for debugging.


TWIG doesn't know how you want to display your table.

By the way, you should consider naming your variable $categories instead of $category, as you table contains several categories.

Then try this:

{% for category in user.profile.categories %}
   {{ category }}
{% endfor %}

If my answer doesn't help, please give us the structure of your array (is there any keys or sub-arrays in you table or is it just a list?)