Does Liquid have a "does not contain" or "not in array" operator?
JekyllLiquidJekyll Problem Overview
When calling items from an array in a Liquid template, how do you call does not contain or not in array?
Jekyll Solutions
Solution 1 - Jekyll
unless to the rescue !
Create an [A, B, C] array.
{% assign input = "A,B,C" | split:"," %}
unless print only if constrain is not met.
This prints nothing:
{% unless input contains 'A' %}No A{% endunless %}
This prints "No Z":
{% unless input contains 'Z' %}No Z{% endunless %}
Solution 2 - Jekyll
you could do something like this:
{% if collection.tags contains 'tag' %}
{% else %}
do stuff!
{% endif %}