(Flask) How to make an If statement in html that detects the last item in a for loop

Question

    <div class="container">
      <div class="row">
        <div class="col-lg-8 col-md-10 mx-auto">
        {% for post in posts %}
          <div class="post-preview">
            <a href="{{ url_for('post', post_id=post.id) }}">
              <h2 class="post-title">
                {{ post.title }}
              </h2>
              <h3 class="post-subtitle">
                {{ post.subtitle }}
              </h3>
            </a>
            <p class="post-meta">Posted by {{ post.author }} on {{ post.date_posted.strftime('%B %d, %Y') }}</p>
          </div>

            {% if post == posts[-1]  %}
              <br />
            {% else %}
              <hr />
            {% endif %}
          {% endfor %}

Im making a web application on flask and this is the snippet of my code to the articles template I have a sqlite database that contains the articles, how can I make an if statement that detects if the post is the last in the loop since im making an hr per article but not on the last one {% if post == posts[-1] %} doesn't seem to work.

Answer 1

By Default Flask uses jinja2 as default Template Engine [1] and that's what you're using. Jinja2 provides loop.last variable [2] that you can use as follows:

<div class="container">
      <div class="row">
        <div class="col-lg-8 col-md-10 mx-auto">
        {% for post in posts %}
          <div class="post-preview">
            <a href="{{ url_for('post', post_id=post.id) }}">
              <h2 class="post-title">
                {{ post.title }}
              </h2>
              <h3 class="post-subtitle">
                {{ post.subtitle }}
              </h3>
            </a>
            <p class="post-meta">Posted by {{ post.author }} on {{ post.date_posted.strftime('%B %d, %Y') }}</p>
          </div>

            {% if loop.last  %}
              <br />
            {% else %}
              <hr />
            {% endif %}
          {% endfor %}