django模板中的If语句

{% if condition %}
    <!-- code to be executed if condition is true -->
{% elif condition %}
    <!-- code to be executed if condition is true -->
{% else %}
    <!-- code to be executed if all conditions are false -->
{% endif %}

{% if user.is_authenticated %}
    <p>Welcome, {{ user.username }}!</p>
{% else %}
    <p>Please log in to continue.</p>
{% endif %}

{% if num > 0 %}
    <p>The number is positive.</p>
{% elif num < 0 %}
    <p>The number is negative.</p>
{% else %}
    <p>The number is zero.</p>
{% endif %}

{% if items %}
    <ul>
        {% for item in items %}
            <li>{{ item }}</li>
        {% endfor %}
    </ul>
{% else %}
    <p>No items found.</p>
{% endif %}