Django chunk filter

chunk.py

from django.template import Library


register = Library()


def chunk(l, n):
    return (l[i:i+n] for i in range(0, len(l), n))


register.filter("chunk", chunk)

usage.html

<div id="empty">{% for chunk in empty|chunk:4 %}

  <ul>{% for item in chunk %}
       <li>{{ item }}</li>{% endfor %}
  </ul>{% endfor %}

</div>


<div id="even">{% for chunk in even|chunk:4 %}

  <ul>{% for item in chunk %}
    <li>{{ item }}</li>{% endfor %}
  </ul>{% endfor %}

</div>

<div id="uneven">{% for chunk in uneven|chunk:4 %}

  <ul>{% for item in chunk %}
    <li>{{ item }}</li>{% endfor %}
  </ul>{% endfor %}

</div>

usage.out

<div id="empty">

</div>


<div id="even">

  <ul>
    <li>0</li>
    <li>1</li>
    <li>2</li>
    <li>3</li>
  </ul>

  <ul>
    <li>4</li>
    <li>5</li>
    <li>6</li>
    <li>7</li>
  </ul>

</div>

<div id="uneven">

  <ul>
    <li>0</li>
    <li>1</li>
    <li>2</li>
    <li>3</li>
  </ul>

  <ul>
    <li>4</li>
    <li>5</li>
    <li>6</li>
    <li>7</li>
  </ul>

  <ul>
    <li>8</li>
    <li>9</li>
  </ul>

</div>

usage.py

# hack the built-in libs for the demostration, use {% load chunk %}
# when you actually put it in your app's templatetags module
from django.template.base import add_to_builtins
add_to_builtins("chunk")

from django.template import Template, Context

t = Template(open("./usage.html").read())
c = Context({"empty": [],
             "uneven": range(10),
             "even": range(8)})

print t.render(c)