For Loop not working in Jinja/Flask

Question

In jinja template my code is something like this, I m trying to get values from my MongoDB database

{% for a in output %}
        {{ a.product_name }}
{% else %}
        <p> No product found </p>
{% endfor %}
Some HTML CODE
{% for b in output %}
         {{ b.product_name }}
{% endfor %}

The problem is first loop is working fine, but second loop not at all working. But when I write the second loop before first loop, then second loop work but then not first loop ( it going inside else and printing "No Product Found").

I am not able to understand this problem.

Answer 1

You want to iterate over the mongodb cursor twice. So after first iteration, you need to call the rewind method on the output (cursor) somewhere between the two loops.

output.rewind()

I am not sure if you would be able to do this in the Jinja template itself.

So the better option would be to convert the pymongo cursor object into a list itself, so you can iterate multiple times.

output_as_list = list(output) 

Now you should be able to use output_as_list in your code the way you expected.