在 Liquid 标签中使用过滤器

Question

I'm using jekyll and Liquid to generate a static web site on github pages.

I want to base some content decisions on whether the amount of content in a document has reached a specific number of works. jekyll has a liquid filter which counts the number of words which I want to use in an if tag. I've tried this:

{% if page.content | number_of_words > 200 %} 
    ...
{% endif %} 

But it doesn't seem to work. I've also tried to assign the result to a variable and use that, and capture the output from the filter. But so far I've had no luck.

Has anyone managed to use a filter in a liquid tag?

Answer 1

{% assign val = page.content | number_of_words %}
{% if val > 200 %}
 ....
{% endif %}

Answer 2

EDIT: This is no longer the most current solution, see and upvote Martin Wang's assign -based solution instead:

 {% assign val = page.content | number_of_words %} {% if val > 200 %} .... {% endif %} >```

At the time this answer was originally written (2011) assign was not a viable solution since it did not work with filters. That feature was introduced one year later, in 2012 .

Leaving my original 2011 answer below in case someone needs to deal with this problem in older versions of Liquid.

---

I don't think it's possible to use filters inside tags that way; it just doesn't seem possible.

However, I've managed to build a set of conditions that might solve your particular problem (discerning wether a page is longer or shorter than 200 words). This is it:

{% capture truncated_content %}{{ page.content | truncatewords: 200, '' }}{% endcapture %}

{% if page.content != truncated_content %}
  More than 200 words
{% else %}
  Less or equal to 200 words
{% endif %}

In order to make the calculations a little more precise, it might be wise to use the strip_html operator. That gives us:

{% capture text %}{{ page.content | strip_html }}{% endcapture %}
{% capture truncated_text %}{{ text | truncatewords: 200, '' }}{% endcapture %}

{% if text != truncated_text %}
  More than 200 words
{% else %}
  Less or equal to 200 words
{% endif %}

Regards!

Answer 3

Just found https://github.com/mojombo/jekyll/wiki/Plugins which gives details on how to write a custom tag for Github. This looks like a possible direction to go as well as providing access to many other customisations from other developers.

Answer 4

{% capture number_of_words_in_page %}{{page.content | number_of_words}}{% endcapture %}
{% if number_of_words_in_page > 200 %} 
    ...
{% endif %} 

Try this.