is there a way to loop over two lists simultaneously in django?

Question

I have two list objects of the same length with complementary data i want to render is there a way to render both at the same time ie.

{% for i,j in table, total %} 
 {{ i }} 
 {{ j }}
{% endfor %} 

or something similar?

Answer 1

If both lists are of the same length, you can return zipped_data = zip(table, total) as template context in your view, which produces a list of 2-valued tuples.

Example:

>>> lst1 = ['a', 'b', 'c']
>>> lst2 = [1, 2, 3]
>>> zip(lst1, lst2)
[('a', 1), ('b', 2), ('c', 3)]

In your template, you can then write:

{% for i, j in zipped_data %}
    {{ i }}, {{ j }}
{% endfor %}

Also, take a look at Django's documentation about the for template tag here. It mentions all possibilities that you have for using it including nice examples.

Answer 2

Use python's zip function and zip the 2 lists together.

In your view:

zip(table, list)

In your template, you can iterate this like a simple list, and use the .0 and .1 properties to access the data from table and list, respectively.

Answer 3

If it's just the variables i and j that you're looking at then this should work -

return render_to_response('results.html',
    {'data': zip(table, list)})

{% for i, j in data %}
    <tr>
        <td> {{ i }}: </td> <td> {{ j }} </td>
    </tr>
{% endfor %}

(credit to everyone else who answered this question)

Answer 4

For any recent visitors to this question, forloop.parentloop can mimic the zipping of two lists together:

{% for a in list_a %}{% for b in list_b %}
    {% if forloop.counter == forloop.parentloop.counter %}
        {{a}} {{b}}
    {% endif %}
{% endfor %}{% endfor %}

Answer 5

Rather than using a dictionary (which does not guarantee any kind of sorting), use the python zip function on the two lists and pass it to the template.

Answer 6

You'll have to do this in the view - use the builtin zip function to make a list of tuples, then iterate over it in the template.

Template logic is purposely simple, anything even slightly complex should be done in the view.