title: How to increment a variable on a for loop in jinja template?
body: <p>I would like to do something like:</p>
  <p>variable p is from test.py which is a list ['a','b','c','d']</p>
  <pre><code>{% for i in p %}
  {{variable++}}
  {{variable}}
  </code></pre>
  <p>result output is:<br />
  1 2 3 4</p>