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Loops

Loops let you repeat a section of your template for each item in a list. This is essential for line items, tables, product lists, and any repeating content.

Simple loop​

{
  "products": ["Apple Juice", "Orange Juice", "Pineapple Juice"]
}
<ul>
{% for product in products %}
  <li>{{ product }}</li>
{% endfor %}
</ul>

Output:

<ul>
  <li>Apple Juice</li>
  <li>Orange Juice</li>
  <li>Pineapple Juice</li>
</ul>

Looping over objects​

When your list contains objects (dictionaries), you can access their properties:

{
  "items": [
    {"name": "Widget A", "price": "$10.00"},
    {"name": "Widget B", "price": "$25.00"},
    {"name": "Widget C", "price": "$15.00"}
  ]
}
<table>
  <thead>
    <tr>
      <th>Item</th>
      <th>Price</th>
    </tr>
  </thead>
  <tbody>
    {% for item in items %}
    <tr>
      <td>{{ item.name }}</td>
      <td>{{ item.price }}</td>
    </tr>
    {% endfor %}
  </tbody>
</table>

Nested loops​

You can nest loops for more complex data structures:

{
  "departments": [
    {
      "name": "Engineering",
      "members": ["Alice", "Bob"]
    },
    {
      "name": "Design",
      "members": ["Carol", "Dave"]
    }
  ]
}
{% for dept in departments %}
  <h3>{{ dept.name }}</h3>
  <ul>
    {% for member in dept.members %}
      <li>{{ member }}</li>
    {% endfor %}
  </ul>
{% endfor %}

Loop variables​

Inside a {% for %} loop, Jinja2 gives you some useful built-in variables:

VariableDescription
loop.indexCurrent iteration (1-based)
loop.index0Current iteration (0-based)
loop.firstTrue if this is the first iteration
loop.lastTrue if this is the last iteration
loop.lengthTotal number of items
{% for item in items %}
  <tr class="{% if loop.last %}last-row{% endif %}">
    <td>{{ loop.index }}</td>
    <td>{{ item.name }}</td>
  </tr>
{% endfor %}

Iterating over key-value pairs​

To loop over a dictionary's keys and values:

{
  "fruit": [
    {"key": 1, "value": "Apple"},
    {"key": 2, "value": "Banana"},
    {"key": 3, "value": "Orange"}
  ]
}
{% for item in fruit %}
  {% for key, value in item.items() %}
    {{key}}: {{value}}
  {% endfor %}
{% endfor %}

Next steps​