Display queryset results by month in template - django

Question

Id like to group the results of my queryset in a table by month with the month name as a header for each table.
I have a model like so:
class Tenant(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=30)
telephone = models.CharField(max_length=30)
email = models.CharField(max_length=30)
contract_end = models.DateField(blank=False)
def __str__(self):
return u'%s %s' % (self.first_name, self.last_name)
View like so:
def expired_contracts(request):
now = datetime.datetime.now()
tenant_queryset = Tenant.objects.all()
expired_list = []
for x in range(0, 12):
date = now + relativedelta(months=x)
expired = tenant_queryset.filter(
contract_end__year=date.year,
contract_end__month=date.month
)
expired_list += expired
context = {"expired_list": expired_list}
return render(request, "expired_template.html", context)
Template:
{% for tenant in expired_list %}
<table>
<tr>
<td>{{ tenant.first_name }}</td>
<td>{{ tenant.telephone }}</td>
<td>{{ tenant.contract_end }}</td>
</tr>
</table>
{% endfor %}
I guess I could create a bunch of empty lists and populate them with a loop and if statements, but that seems a little much.
Any other way I could go about this?
Thanks!

Answer 1

itertools.groupby() is an excellent tool for grouping your list.
First you should order your object by the attribute that you are grouping by
tenant_queryset = Tenant.objects.order_by('contract_end')
Grouping by month can be achieved by using itertools.groupby and formatting the date as the month's name as a string date.strftime('%B')
context = {
"expired_list": itertools.groupby(
expired_list,
lambda t: t.contract_end.strftime('%B')
)
}
You can then loop over the months and the tenants for that month in the template like so
{% for month, tenants in expired_list %}
<h3>{{ month }}</h3>
<table>
{% for tenant in tenants %}
<tr>
<td>{{ tenant.first_name }}</td>
<td>{{ tenant.telephone }}</td>
<td>{{ tenant.contract_end }}</td>
</tr>
{% endfor %}
</table>
{% endfor %}