getting number of days between twoo dates - django

Question

I don't figure out how to get the number of days betwen twoo dates:
this is the models I have :
class Reservation(models.Model):
"""A typical class defining a reservation model."""
# Fields
id_reservation = models.BigAutoField(primary_key=True)
start_date = models.DateField(auto_now=False, auto_now_add=False)
end_date = models.DateField(auto_now=False, auto_now_add=False)
client_id = models.ForeignKey(Client, on_delete=models.CASCADE)
chambre_id = models.ForeignKey(Chamber, on_delete=models.CASCADE)
# Metadata
class Meta:
ordering = ['-end_date']
# Methods
def get_absolute_url(self):
"""Returns the url to access a particular instance of MyModelName."""
return reverse('model-detail-view', args=[str(self.id_reservation)])
def __str__(self):
return self.id_reservation
and try to calculate the days between the end_date and the start_date in my generic view:
class ReservationsListView(generic.ListView):
"""ReservationsListView: produce a list of all Reservations """
model = Reservation
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context['periode'] = Reservation.end_date-Reservation.start_date
return context
can please help doing this.

Answer 1

You can subtract the two date objects, and then obtain the .days attribute, so:
class Reservation(models.Model):
# …
#property
def days(self):
return (self.end_date - self.start_date).days
This will thus return the difference in days, so that means that if we calculate the difference between today and yesterday, this will result in one day:
>>> (date(2021, 4, 28) - date(2021, 4, 27)).days
1
If you want to take both days into account, you increment the result with 1:
class Reservation(models.Model):
# …
#property
def days(self):
return (self.end_date - self.start_date).days + 1
You can thus retrieve the number of days from a Reservation object with:
my_reservation.days