how to calculate due date in django based on existing date-CodePudding

How do i calculate the due date from this model based on the date renewed. i want the due date to be 5 years after the date Renewed.

I'm pretty stuck. I need help.

This is my models.py file in Django

    def get_deadline():
    return dateRenewed()   timedelta(days=1825)

    class Trademark(models.Model):
        trademarkName = models.CharField(max_length=100)
        trademarkClass = models.CharField(max_length=100)
        dateCreated = models.DateTimeField(default=timezone.now)
        acknowledgeDoc = models.FileField(upload_to='acknowledge_docs', default='default.jpg')
        acceptanceDoc = models.FileField(upload_to='acceptance_docs/', default='default.jpg')
        cert = models.FileField(upload_to='trademark_cert/', default='default.jpg')
        renewalDoc = models.FileField(upload_to='renewalDocs', default='default.jpg')
        dateRenewed = models.DateTimeField(auto_now_add=False, auto_now=False, blank=True, null=True)
        duedate = models.DateTimeField(default=get_deadline)
        uploadedBy = models.ForeignKey(User, on_delete=models.RESTRICT)
    ```

CodePudding user response：

You can use timedelta to add the years:

from django.utils import timezone

delta = timezone.timedelta(days=365*5) # create a timedelta object

duedate = dateRenewed   delta

This doesn't handle leap years, though.

Accounting for leap years

The above code always counts 365 days for every year. But if you want to account for leap years, you'll need to add an extra day for every leap year:

import calendar
from django.utils import timezone

year_1 = dateRenewed.year
year_2 = year_1   5
leap_days = calendar.leapdays(year_1, year_2) # count leap days between two years
total_days = (365 * 5)   leap_days

delta = timezone.timedelta(days=total_days)

duedate = dateRenewed   delta

CodePudding user response：

I found a way to do it.

It's by using

    @property
    def Shelf life(self):
        return self.dateRenewed   datetime.timedelta(days=365*5)