How to use multiple arguments in an if statement with Liquid

问题

I want to use an if statement in Liquid with multiple conditionals. Something like:

{% if (include.featured == "true" and product.featured == "true") or (include.featured == "false" and product.featured == "false") %}

Multiple conditionals don't seem to work. Have I got the syntax wrong or can Liquid not handle this sort of if statement?

回答1:

Unfortunately, Liquid has a poor implementation of boolean algebra.

Using Liquid's operators and tags, here is a dirty way to achieve it:

{% if include.featured == true and product.featured == true %}
      {% assign test = true %}
{% endif %}

{% if include.featured == false and product.featured == false %}
      {% assign test = true %}
{% endif %}

{% if test %}
      Yepeeee!
{% endif %}

回答2:

Another way you can condense this is to combine else if statements, and booleans don't necessarily need the "==" when evaluating true:

{% if include.featured and product.featured %}
      {% assign test = true %}
{% elsif include.featured == false and product.featured == false %}
      {% assign test = false %}
{% endif %}

来源：https://stackoverflow.com/questions/23054564/how-to-use-multiple-arguments-in-an-if-statement-with-liquid