CODEWITHSUNDEEP
djangodjango-templatesdjango-views
Aman Bhatnagar
Aman Bhatnagar

Reputation: 67

How to perform calculation for a model field and display the value in the template?

I have a model called 'Candidate', which has the fields Experience,New Experience,Date_posted.

I'm using CreateView form to store the values in the database. When I enter experience and date_posted(set to timezone.now) for the first time, the 'new experience' value should also be set to 'experience' value by default. Now this 'new experience' value should get incremented after every month.

For example, experience=2.4 ( 2 years 4 months ), new experience =2.4( set automatically )

So, If I open my template(website page) 1 month from now, the 'experience' and 'date_posted' values must be same, but 'new experience' = 2.5 ( 2 years, 5 months )

class CandidateCreateView(LoginRequiredMixin, CreateView):
   model = Candidate
   fields = ['candidate_name', 'experience', 'email', 'new_experience']

   def form_valid(self, form):
        form.instance.author = self.request.user
        return super().form_valid(form)

Also, I want to use the format, 2.12 ( for 2 years 12 months )and 3.1 ( for 2 years 13 months ). How do I achieve this?

Upvotes: 0

Views: 212

Answers (1)

motatoes
motatoes

Reputation: 926

Maybe you can set your new_experience as a computed property, rather than a normal field?

from datetime import datetime

class Candidate:
    # ...
    experience = models.DateField()

    @property
    def new_experience(self):
        now = datetime.now().date()
        delta = now - self.date_posted
        return (self.experience + delta)

 Update

After your clarification in the comments, my suggestion would be to split the experience field into years and months:

class Candidate:
    # ...
    experience_years = models.IntegerField()
    experience_months = models.IntegerField()



    @property
    def new_experience(self):
        base_experience = datetime.datetime(year=self.expreience_years, month=self.experience_months, day=1)
        delta = datetime.datetime.now() - self.date_posted
        new_experience = base_experience + delta
        # now you can access new_experience.year, new_experience.month
        return new_experience

Another option be can be to return a tuple from new_experience (years,months), as computed above

Warning: Quick and dirty but not tested

Upvotes: 1

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