Cycle tag - last cycle returns same cycle

Question

I have this code:

{% for entry in craft.entries.section('gigs') %}
    <h2 class="{{ cycle(['odd','even'], loop.index0) }}">{{ entry.title }}</h2>
{% endfor %}

This returns the same cycles for the last two entries like so:

<h2 class="odd">Title 1</h2>
<h2 class="even">Title 2</h2>
<h2 class="odd">Title 3</h2>
<h2 class="even">Title 4</h2>
<h2 class="odd">Title 5</h2>
<h2 class="odd">Title 6</h2>

No matter how many entries, the last two entries have always the same class. Why is that?

Edit: Okay, I figured the problem. It's not a bug:

I filter the entries by date:

{% set present = now|date_modify("-1 day") %}
{% for entry in craft.entries.section('gigs') %}
   {% if entry.datum < present %}
       <h2 class="{{ cycle(['odd','even'], loop.index0) }}">{{ entry.title }</h2>
    {% endif %}
 {% endfor %}    

so the cycle filter works, but since some entries are filtered the odd/even schema doesn't work any longer. I guess I have to filter the entries first and then apply the cycle filter. But how would I have to write do that?

Answer 1

As you already found out, the loop.index counter increments for each iteration of the loop, not only if you use or print it within your conditional. The best solution to work against it is to get rid of that conditional.

In this case it is in fact possible to catch only those entries you are after, making the conditional redundent

{% for entry in craft.entries.section('gigs').datum('< ' ~ present) %}
    <h2 class="{{ cycle(['odd','even'], loop.index0) }}">{{ entry.title }</h2>
{% endfor %}

if it wasn't, you could have done your own counter that increments within the conditional.

{% set index = 0 %}
{% for entry in craft.entries.section('gigs') %}
    {% if entry.datum < present %}
        {% set index = index + 1 %}
        <h2 class="{{ cycle(['odd','even'], index) }}">{{ entry.title }</h2>
    {% endif %}
{% endfor %}