Assigning a custom field date to a variable in LocomotiveCMS

I'm trying to assign a date to a variable, for the purpose of breaking up the layout. Perhaps there's a better way to do this, so feel free to recommend alternatives.

I have a model for news_items, with a date field called news_date. I want to go through each of the model entries and start a new section whenever a new year is encountered. My plan was pretty basic:

{% assign curYear = "" %}
{% for news in contents.news_items %}
  {% assign prevYear = curYear %}  
  {% assign curYear = news.news_date.year %} <-- this does not work
  {% if prevYear != curYear %}
    <h1>Press Releases for {{ news.news_date | format_date: '%Y' }}</h1>
  {% endif %}
  <p>{{curYear}}</p> <-- this is always empty
  <p>{{news.content}}</p>
{% endfor %}

I tried various other syntaxes, like Time.parseTime(news.news_date).year, but it seems like you can't do arbitrary Ruby in Liquid. Is there some way to achieve what I want, here?

Thanks for your assistance!

Solution

Thanks to a helpful person on the google group, the capture tag was pointed out to me, which captures things that would be otherwise output on the page into a variable:

Instead of this (or the various iterations I tried with assign):

{% assign curYear = news.news_date.year %}

This works perfectly well, taking advantage of the format_date filter:

{% capture curYear %} {{ news.news_date | format_date: '%Y' }} {% endcapture %}