How to increment the counter inside a Liquid for loop?

Question

I am struggling to figure out how to increment the index variable within a for loop in Liquid/Jekyll. Currently, I have something along the lines of

{% for i in (0..num_posts) %}
    {% if i < some_value %}
        do_thing
    {% else %}
    {% endif %}
    {% assign i = i|plus:1 %}
    {% if i<some_value %}
        do_another_thing
    {% else %}
    {% endif %}
{% endfor %}

The problem is, instead of incrementing i, it leaves i as the same value.

Things I have tried:

1. Using {% assign i = i|plus:1 %}.
2. Using {% increment i %}.

3. Using

   {% assign j = i|plus:1 %}
   {% assign i = j %}
   

I can't use the offset command either since the code doesn't always check only 2 if statements in the loop.

Any ideas?

Answer 1

Here i is not the index. To get the current index use {{ forloop.index }}.

{% if forloop.index < 5 %}
    Do something
{% endif %}

To assign your own custom index inside a loop you may use something like:

{% assign i = 0 %}
{% for thing in things %}
    {% assign i = i | plus:1 %}
{% endfor %}