CODEWITHSUNDEEP
javascriptdjango
kh_one
kh_one

Reputation: 257

Extracting min and max value of Django model feature in template

I have a model like this:

class Integer(models.Model):
    integer_value = models.IntegerField(default=0)
    current_price = models.DecimalField(max_digits=5, decimal_places=2, default=0.00)
    share = models.IntegerField(default=0)
    market = models.ForeignKey(
        IntegerMarket,
        on_delete=models.CASCADE,
        related_name='integers',
        default=None)

    def __str__(self):
        return str(self.integer_value)

    class Meta:
        ordering = ['integer_value']

I'm using the following view:

class IntegerMarketDetailView(LoginRequiredMixin, DetailView):
    model = IntegerMarket
    template_name = 'integer_market_detail.html'
    login_url = 'login'

In my template, which is for a given instance of IntegerMarket, I would like to extract the minimum and maximum values of integer_value, in order to then define the min and max value of an axis in JavaScript.

For example, I might have an instance of IntegerMarket featuring five integers, with integer_value 1 through 5, respectively. I would then like to extract 1 as min and 5 as max.

What's the most straightforward way to do this?

Upvotes: 0

Views: 1388

Answers (2)

dirkgroten
dirkgroten

Reputation: 20672

Given an instance integer_market of IntegerMarket, you can get all the related Integer instances using .integers since you nicely set that as related_name.

Now you can just do an aggregation using Max and Min.

from django.db.models import Max, Min
integer_market.integers.aggregate(Max('integer_value'), Min('integer_value'))

>> {'integer_value__max': 10, 'integer_value__min': 0}

Upvotes: 1

416e6f6e
416e6f6e

Reputation: 51

Django offers max and min values to be defined in queries.

from django.db.models import Max, Min

Then when defining your query you'll have something like 

my_query = models.IntegerMarket.objects.all().annotate(max_integer=Max('integer_value')).annotate(min_integer=Min('integer_value'))

Then you can call those values in your view using max_integer/min_integer or whatever you named it.

Upvotes: 1

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