CODEWITHSUNDEEP
djangodjango-templates
John
John

Reputation: 47

Django - template filter tag to change value of a variable for every 'x' th iteration in a for loop

in views.py

def index(request):
    all_user = Manvi_User.objects.all()
    ordering = all_user.order_by('dob')

    return render(request, 'index.html', {'ordering': ordering})

in My tag.py

@register.assignment_tag

    def year():

    return "2017"

In my index.html

{% year as years %}
    {% for Manvi_User in ordering %}

    <li>{{ Manvi_User.first_name }}</li>
    {{years}}
    {{ Manvi_User.dob}}


    {% if forloop.counter|divisibleby:3 %}
    {{ years = years+1}}

    {% endif %}

    {% endfor %}

I get problem at

years = years +1

I want to display starting first 3 name with year 2017 then 3 name with year 2018 and next 3 name should be with year 2019

Upvotes: 1

Views: 732

Answers (1)

at14
at14

Reputation: 1204

Pass the forloop counter value to a custom template filter tag, perform your calculations there and then return it. Although, it's best to keep logical code restricted to the view - you should see if there is any way to move this piece of code to your view

my_tag.py,

from django import template

register = template.Library()

@register.filter
def calculate_year(year, loop_counter):
    try:
        year = int(year)
    except ValueError:
        return None
    else:
        return str(year + (loop_counter//3))  # This will work on python 2.x and 3.x
        #return str(year + (loop_counter/3))  # This will not work on python 3.x

in your template,

{% load my_tag %}

<!-- Some code inside your forloop -->

{{year|calculate_year:forloop.counter}}

Upvotes: 1

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